35d worsening gas mileage - solved- thermostat/fan/EGR cooler - DIY with pics
 

I have a 2010 e70 35d with about 79,000 miles. Over the past 6 months or so I've noticed a drop in highway mpg from 31-32 to approx 25-26. After checking out a number of forum discussions (particularly bimmerfest and some European 335d forums), I thought possibly my thermostat was malfunctioning, with resultant low engine temps. Apparently, a low engine temperature can cause a number of issues - poor engine efficiency, plus some say the glow plugs stay on for temps <75 deg cent (may cause eventual early demise of glow plugs), and numerous people say the diesel particulate filter (DPF) regeneration mode requires a temp of 75-80 deg cent. So a low engine temperature for the diesels may cause poor mpg, burn out of glow plugs, and DPF malfunction.

This link on bimmerfest gives an excellent overview of the issue. As said by lpcapital in post #5:

"While on a gasoline car if the engine temperature is a 10 or so degrees lower than optimal nothing major happens, the same is not true with our cars where the regeneration of the DPF occurs only if the coolant temperature is at a particular level, which appears to be 75C. There are plenty of reports of aged thermostats that keep the engine in the low 70s when cruising on freeways. Since the coolant temperature is below the threshold, the DPF doesn't regenerate, it clogs and people lose their mind figuring out what's wrong and start spending thousands to replace DPF and adding washes, remove the DPF all together."

So I utilized the "hidden menu" as discussed in post #17 of the above link to check my operating temp. My temp (like many in other forum postings) was 72-73, and never over 75. BTW, post #17 talks about accessing the hidden menu with the ignition on, but engine off. If you do this, there is obviously no way to monitor coolant temperature while driving. No worries, though, you can access the hidden menu in the same way, but with the engine running. So start the car, idle in the driveway, and have a button pushing frenzy as described in post #17.

The forums I've read express some uncertainty about what the operating temp is supposed to be, but (spoiler alert!) after getting to my thermostat it turns out that "88C" is clearly printed on the thermostat:

http://www.xoutpost.com/attachment.p...1&d=1420410407

And after I replaced the thermostat, my new operating temp was 85-86 deg, and mpg was back to 31-32 on the highway. So I'm pretty pleased. Here is a DIY for this job.

To begin with, you'll need the usual assortment of sockets, including torx sockets, e-torx sockets, and socket extensions (it will be critical to have a roughly 7-8 inch reach from tip of a t-45 socket to end of socket extension(s) to get to the exhaust gas recirculator (EGR) cooler flange bolts). A mirror was a huge help in seeing back into the "guts" of the engine/EGR cooler interface. In addition, I highly recommend a "tight reach ratchet" to get to many of the bolts in tight spaces. [Edit on 12/18/16 - see post #180 - Andras comments that the tight reach ratchet is not absolutely necessary. I agree. I have since realized that if one removes the fan/shroud before removing the air ducts, then there is a lot more room to get to the air duct clamp bolts and the tight reach ratchet is not essential. But still, it's kind of a cool tool and might be nice to have in your box.] Here's a picture of the tight reach getting to a difficult to access clamp bolt - as viewed from the top:

http://www.xoutpost.com/attachment.p...1&d=1420410407

And here's a view of it down in the deep:

http://www.xoutpost.com/attachment.p...1&d=1420410407

There are a lot of connections, so I used bits of blue painter's tape as tags to mark every hose/electrical connector I took apart - that way I made sure I didn't forget to hook something back up. A very short (!) summary of the process is in post #15 of the above bimmerfest link. Understand that you'll need to remove the air ducts (both pre and post MAF), remove the engine cross bar, disconnect coolant hoses, remove the fan/fan shroud, remove EGR cooler (IMO this is the tough part), and now you've got access to the thermostat. It took me a little over 6 hours, though I was moving slowly so as not to make a mistake. Some more details:

Start by removing the engine cross bar, and then disconnect the cable (?others have said this is hood release cable, but I don't know for sure?) that is attached to it. There is an electrical connection bracket attached to the cross bar - this needs to come off too.

The bottom plastic skid plate needs to come off, otherwise the drained radiator fluid will splash (more) and make an even bigger mess.

Next, begin draining most of the radiator. I couldn't find a drain bolt for the radiator, and ended up disconnecting various hoses at various times. I had a scavenger bucket, but (as noted above) still probably 25% went on the floor. Have a bunch of towels around to clean up the mess. **Edit 12/18/16 - see post #180 where Andras describes which radiator hose to disconnect which allows fluid drainage with minimal spilling/mess.**

Removing air ducts pre and post intake muffler/MAF - see the Realoem link (below) to see what I'm talking about.

http://www.realoem.com/bmw/diagrams/l/q/264.png http://www.realoem.com/bmw/images/diag_3w9m.jpg

You'll want the tight reach ratchet to get to some of these duct clamp bolts. *Edit 12/18/16 - As noted above, in post #180 Andras points out the tight reach is not absolutely necessary. If you remove the fan/shroud before working on the duct clamp bolts then you can get by without it. Your choice.* The intake muffler (#1 in this link - see below) is removed by giving a good upward tug on the "legs" and main body of the intake muffler.

http://www.realoem.com/bmw/diagrams/d/z/250.png http://www.realoem.com/bmw/images/diag_3j3x.jpg

Remove fan/shroud: Remove the electrical connection on passenger side. Also remove the bracket (part 18 in below diagram - held on with a torx bolt) that holds the air hose coming from the intercooler to the throttle/EGR valve on the driver's side (the air hose I'm talking about is part #12 in this link - see below). Also, disconnect this air hose (and it's electrical connection) from the throttle body so it can be pushed out of the way so the fan/shroud can come out. ***Edit December 2016 - check out this link for a great DIY on bimmerfest that provides a lot of detail and pictures for removing the fan. The link is for a DIY on idler pulley belt tensioner, but there is a detailed description for removing the fan.***

http://www.realoem.com/bmw/diagrams/t/e/364.png http://www.realoem.com/bmw/images/diag_5dkj.jpg


Also remove the main coolant hose that enters the top of the radiator on the driver's side (part #1 in this link - see below).

http://www.realoem.com/bmw/diagrams/n/q/272.png http://www.realoem.com/bmw/images/diag_3wpq.png

Now you should be able to lift the fan/shroud out without obstructions. There are two flanges/flaps/tabs (one on driver's side and one on passenger side) about six to eight inches down on either side that slide into slots to keep the fan and shroud in position. Use a screwdriver to press the flange in, and then you can lift the fan/shroud up a couple of inches. Once it's been lifted a few inches, be aware that the flange/flap/tab on the driver's side is hinged, and needs to be flipped inward (photos below will hopefully make this clear) to clear obstructions and allow the fan to be lifted out. Here is an overview pic of the fan/shroud with an arrow pointing to the "flippable flap" -


http://www.xoutpost.com/attachment.p...1&d=1420410407

Here is another up close pic - the "flippable flap" (red arrow) has now been flipped open. The yellow arrow shows the slot mechanism that helps keep the bracket for the charge air hose leading to the throttle (noted above) in position.


http://www.xoutpost.com/attachment.p...1&d=1420410407


Removal of the EGR cooler. The EGR cooler sits above the thermostat. The EGR cooler can be seen in this RealOEM link. See below - it is what hoses 6 and 7 connect to.

http://www.realoem.com/bmw/diagrams/t/w/274.png http://www.realoem.com/bmw/images/diag_3y3a.jpg

For another view, it is the big shiny rectangular metal object in the center of this pic:

http://www.xoutpost.com/attachment.p...1&d=1420396725

Undo the various electrical connections, the radiator hoses (6 and 7 as noted in the RealOEM link above), and the circumferential clamp (red arrow in photo above) that connects the cooler to the EGR valve. There was another connection (yellow arrow) that leads to a particularly difficult (for me, at least) electrical connection on the EGR valve. This electrical connection is shown in the next photo:

http://www.xoutpost.com/attachment.p...1&d=1420399274

I expected this electrical connection to easily come apart when the white tab was snapped back. However, I couldn't get it to come apart. Eventually, I was able to get it apart by slipping a very small flat screwdriver blade between the two connection parts as shown in the photo above. Then it disconnected easily. Not sure if I was doing something wrong, but I couldn't get it apart any other way (edit point: be aware the photo above was taken after completion of this job in order to document this (for me) difficult electrical connection. When I was actually doing the job the black plastic "leg" of the intake muffler that is obscuring the view of the screwdriver in the photo had been removed). Edit 4/21/2016 - See post #159 for great information from Shaman on how to remove this connector - it involves sliding the white tab back, then pinching/compressing it to release the locking tab.

Disregarding electrical/vacuum connections, the EGR cooler is held in place by a total of five connection points - the circumferential clamp discussed above, two mounting bolts (easy to see), and by two flange bolts that are hidden underneath (and to the side of) the vacuum pump. The vacuum pump is the large silver circular object sitting above the EGR cooler in the photo above. The two EGR cooler flange bolts were/are the tough part, IMO. I could barely see the top flange bolt by peering in between various vacuum hoses and electrical cables. The only way I could see the bottom flange bolt was with a mirror. The flange bolts are T45. You'll need an extension set that measures roughly 7-8 inches from the tip of the torx socket to the end of the extension set. I could see enough to get the socket into the top bolt, but had to use a mirror and "memory braille" to get into the bottom bolt. Here is an overview picture of the socket/extension/wrench on one of the bolts:

http://www.xoutpost.com/attachment.p...1&d=1420402028


And here is a picture taken that (I hope) demonstrates using the mirror to confirm visualization of the proper placement of the socket on the top flange bolt.

http://www.xoutpost.com/attachment.p...1&d=1420402200

The camera is pointed toward the front of the car, so the reflection in the mirror is toward the rear of the car. The red arrow shows the socket in place on the top flange bolt.

I undid the flange bolts first, then the mounting bolts. The flange bolts stayed in place on the flange as the EGR cooler was removed. I was terribly afraid that once loosened I would drop the flange bolts deep into the engine compartment - never to be found again. So I stuffed a rag under the flange area (poked it into position with a screwdriver) so that if they fell they would be saved by the rag rather than drop down into the abyss.

At this point, I was able to easily lift the EGR cooler out of the way and place it on top of the engine. With the EGR cooler out of the way, the thermostat replacement was straightforward - 2 hoses and 4 bolts (though the rigid water pipe on the driver's side of the thermostat [part #1 on this link from RealOEM - see below] has a positioning bolt (I think it's part #3) that needed to be removed to allow thermostat removal).

http://www.realoem.com/bmw/diagrams/t/w/274.png http://www.realoem.com/bmw/images/diag_3y3a.jpg

Here is a picture with the thermostat out and the EGR cooler sitting on top of the engine:

http://www.xoutpost.com/attachment.p...1&d=1420402522

The single red arrow shows where the thermostat was removed. The double red arrows point to where the mounting bolts go. The EGR flange that accepts the flange bolts I discussed at length above is shown by the yellow arrow. The green arrow leads to the difficult electrical connection I talked about earlier.

Putting back together was not too bad, with a couple of caveats:

1) A lot of connections. Again, I recommend tagging things with tape so you make sure you don't miss something.

2) The EGR cooler flange bolts (again!). You can't reach the flange with your fingers to start the bolts. The bolts have to be attached to the 7-8 inch extension and then carefully (memory braille on the bottom bolt, again) put into position. I didn't want to drop the bolts, so had a cloth in position under the flange to catch a potentially dropped bolt. In addition, I stuck some blue painter's tape on the end of the T45 socket (adhesive toward the socket) and then pressed the bolt onto the socket. The tape gave enough friction so that the bolt was held on quite securely. Here is a pic of what I'm talking about - here I have an e-torx socket attached to the torx socket instead of the bolt, but hopefully you understand:

http://www.xoutpost.com/attachment.p...1&d=1420397578

The EGR cooler flange bolts are not magnetic, so a magnet would be no help in retrieving a dropped bolt.
(edit point added) - Also, see ZetaTre post # 14 on this posting for one suggested way of tightening the various EGR connection bolts. Also, ninja zx11 has a posting (link is here) which includes a detailed description of the order in which to tighten bolts, and the torque settings.

3)When you put the fan/shroud back in place, be aware there are tabs at the bottom of the shroud that fit into slots near the bottom of the radiator. The diagram (RealOEM link is here) below has the number 4 pointing to one of the bottom tabs of the shroud. In case you're wondering why you can't see any tabs on the top of the shroud, that is because the top of the shroud has slots (rather than tabs). So (not counting the charge air hose bracket) the fan/shroud has a total of 6 connection points - 2 slots/tabs on the bottom, 2 flaps that clip in on the sides (driver's side has the "flippable flap"mentioned above), and 2 smaller slots/tabs on the top).

http://www.realoem.com/bmw/diagrams/v/n/247.png http://www.realoem.com/bmw/images/diag_3mz6.jpg


As I said, it took me about 6-7 hours, but I was going really slowly. Overall difficulty - I'd rate it as about a 6 on 1-10 scale.

Even though the ultimate goal is a thermostat change, the difficult parts were getting the fan/shroud out, and the EGR cooler out.

As I said, my mileage has improved, and hopefully I've saved my glow plugs and DPF!

Hope the above is helpful.

Stephen
1998 ML 320 - now driven by son #1
2005 e53 3.0 - now driven by son #2
2008 ML320 CDI - now driven by wife
2010 e70 35d - now driven by me

Extra pics for above initial post
 

Above post edited for clarity and photos.




https://www.dropbox.com/s/eo7bksx4v5...ostat.jpg?dl=0http://www.xoutpost.com/data:image/p...AASUVORK5CYII=

Thanks for the write up! We've got a 2010 35d too with about 72,000 miles. Sad that these things can't even make 100k miles without needing some repairs on parts that should realistically last much longer.

Nice writeup and thanks for sharing the pictures....
I am also in the process of changing the thermostat too on my 2009 x5 35d with 88000kms.Mine temp stays 73~76 which is not normal operating temp.

Just a side note:I have monitored my DPF regens with BMWHAT app and actually it starts as soon as the engine coolant temp reaches 60 deg. Celsius.But i am not sure about glow plugs remain activated until 75 deg Celsius.But all the documents i read from BMW itself were saying min 75 deg Celsius for DPF regen.I think they changed it to 60 deg later DDE software updates.Mine DDE was last updated in 2012.My bmwhat log is located here:

Bmwhat's app log while regenerating .

Thanks for taking the time to put this together!

(Why is BMW so challenged with thermostats???)

+1...as I mentioned in the other 'Diesel Thread', my curiosity on a diesel as a potential replacement for our 13+ yr old E53 is the reason for my interest in these kinds of threads.

I fully realize all cars are mechanical and things break/wear out but some of these stories on the diesels make me wonder how BMW sourced parts and components that seem to fail so early in the life cycle.

The ~$7000 'particulate filter 'job quoted in another thread is another example.

I understand the anecdotal nature of 'this needs repair' or 'that part needs fixing', and that many of us have gotten ~100k miles or more out of their Xs, but most of those stories seem to be from the E53 models vs the newer E70s.

Regardless of how exciting or cool or fun these cars are, (BMWs in general), most/all of the engine, trans and running gear parts/systems should perform for ~100k miles, imo. Maintenance items I get; 'standard' components & systems that seem to last longer on many other species of cars, don't 'seem to' on these babies.

It is almost as if the 4yr/50k mile deal is the 'happy time' and then the poor next owner, or even orig owner is just waiting for the shoe to drop...

I love our '01 E53, and I have been very lucky over the years. But, the stories and my own sense of pessimism give me pause on my own car, as do they diesel stories, in considering a new X, gas or diesel.
GL, mD

PS: Helluva write up by sgrice, by the way. :thumbup:

Good job!!!! [I'm lpcapital elsewhere, so thanks for the quote]

I've been there and done that.

As I stated elsewhere this whole thing started after my dad has been battling with failed glowplugs and clogged DPF. The root cause of it all was the engine not maintaining normal operating temperature (defined as >75C) resulting in running in warmup mode (i.e. overfueling and glow plugs under light to medium load) and failing to carry out regular DPF regen. Restarting the regen was a bit more tricky since it required fooling the DDE in reading lower backpressure which we resolved using the hose with a slit.

In the midst of all that I check the coolant temperature in my 35d and noticed like you did that it was getting too low while coasting or under light load. Like you observed engine temperature became much more constant after replacing it.

My recommendation would have been to also replace the thermostat on the transmission heat exchanger, just because BMW has challenges with thermostats, you are already draining the system and it's cheap.

The other recommendation would be to put some anti-seize compound (the same used on spark plugs) on the flange bolts. The are high carbon steel bolts going into cast iron so they seize up like crazy and may make you think they are tight when they are only struggling through.

Last but not least, have you gotten the bracket installed under the EGR valve (I can't seem to see it from the pix you posted): if not call your local dealer, tell them to run your VIN to check for any open campaign. The bracket support the EGR and reduces the risk of breaking around the flex joint. Here's the link to the bulletin: https://drive.google.com/file/d/1mDX...ew?usp=sharing

scollins - I'd be really curious to know what what your operating coolant temp is. Check out the "hidden menu" discussed above, and you can monitor your coolant temp in real time. If it's in the 73-75 degree range, then I bet you could improve your gas mileage (and maybe preserve your DPF and glow plugs) with a thermostat change. But I do agree with you and ard that one would think the thermostat should last longer (though if it's going to fail, I'm glad it seems to fail open rather than closed).

motordavid - Glad you've been so happy with your e53. I was very happy with mine, hence my subsequently getting the e70. I share some of your frustrations, but overall I think the e70 mechanical experience has been pretty similar to the e53. The e53 that is now driven by one of my sons has roughly 125,000 miles. I had essentially no issues until around 90,000 miles. Then I had what I believe are the usual issues of a "middle aged car" - valve cover gasket, oil filter housing gasket, CCV system (kudos to the Bavauto video on Youtube for that repair), both front control arm bushings, both front CV boots (ditto kudos to the "30 minute CV boot repair" guide on this forum), belt tensioner, idler pulley, and some leaking transmission cooler and power steering hoses. In addition, replaced the thermostat, water pump, and expansion tank as a precaution after hearing about a number of problems from others. With the e70 35d, the only issue I've had (other than the thermostat issue discussed now) has been leaky gaskets on the red charge air hose leading to the intercooler. So I don't think I have too much to complain about for nearly 80,000 miles. Hope I didn't just jinx myself.

ZetaTre - Good to have you chime in, and thanks for all your prior posts. As I stated, some of your posts are what led me to this solution. I saw that you had recommended the transmission thermostat as part of the repair job, but I must confess I just let that sleeping dog lie. I felt that I had enough on my hands as it was. Hope I don't regret it. Great information about the service bulletin on the EGR bracket!! I had no idea, and the work has not been done to my car (since being out of warranty I've done my own maintenance, so it hasn't been in the dealership for awhile). But now I have an appointment for next week to get the bracket put on. Thanks again - you may have saved me from one of the leaking EGR coolers I've read about! I'm a little confused about what you meant by anti-size on high carbon steel flange bolts. What I referred to in my post as "flange bolts" are the part #6 torx bolts in the the diagram below that connect the flange on the semi-flexible hose end of the EGR cooler. These T45 torx bolts are not magnetic. I assume you are talking about the 13 (or 14?) mm hex bolts (part #4) that I referred to as "mounting bolts". Those are magnetic. Anyway, I didn't put any anti-seize on them, but I will when I next do some work in this area!

http://www.realoem.com/bmw/diagrams/j/n/284.png




In addition, I've followed your oil catch can efforts with admiration. Are you happy with your current system, or are you in the midst of another iteration?

Thanks again for the heads up about the mounting bracket service bulletin.

I was referring to the #6 bolts: they bolt into the exhaust manifold which is cast iron. I said before they are made of high carbon steel which is probably incorrect since they are not magnetic. In either case I've put the antiseize compound on them because as I was turning them I noticed they were seizing very easily. I was going to put some grease on them, but the being exhaust it would have burnt off right away.

About the oil separator I'll update that thread next so we keep this conversation on topic.

I was thinking to install this bracket,but looks like after instalation the lower(intake) pipe of the EGR starts to break,with very bad effects.In more than a few cases the exhaust gasses escaping from a crack on the bottom pipe burn through the plastic T-stat housing.

What's the source? It's the first time I read this...

http://www.xoutpost.com/bmw-sav-foru...el-pain-4.html
Post # 38
Plus 2 my customers and a friend in texas.

Interesting indeed... I may start hang around here a bit more... The other board has a lot more nonsense going on and I miss all these cool stories

I gave some more thoughts about the new bracket being the reason for the rapture and I'm not entirely convinced.

There are 2 bolts that secure the cooler to the head/engine block which make it for a very rigid and solid mounting point. I can't see how the bracket mounted all the way over to the opposite side of the accordion that cracks would affect the rigidity of the accordion itself.

I do, however, have a theory on how it cracks which is improper alignment during assembly of the EGR cooler. Perhaps the cases reported (and others for that matter) had the EGR cooler cracked so as described in the bulletin, it was going to be replaced as part of the bracket installation.

The technician, for example, could have first bolted the cooler to the engine block that secured the two bolts on the flange that connect the cooler to the exhaust manifold. As a result he flange may have not been properly aligned resulting in stressed on the accordion that through the because of the heat cycles ultimately cracked.

I can't recall off the top of my head if INPA/DIS have a specific tightening sequence required, but when I reassembled my cooler after replacing the thermostat I:
1) loosely place the two bolts that attach the cooler to the engine block
2) position the flange and tight the two bolts
3) positioned the clamp over the EGR valve and secured it
4) went back and torqued the two bolts on the flange
5) torqued the two bolts that secure the cooler to the head
That came just as common sense to me since I've been wrenching for some time, but who knows if the ASE and BMW certified monkey at the dealership takes the same care...

Nonetheless, I could be entirely wrong... I'd just be very curious to understand how the bracket on the outlet side of the EGR cooler in question affects the accordion on the inlet...

The cases of the accordion cracking are reported after instalation of the bracket,I didnt hear of any original EGR to crack there.The EGR is exposed to a substantial thermal and pressure loads.Especially the accordion is on the hot and pressure side of the turbo.The EGR may go thru many heat cycles while driving in city or mixed as the valve may open or close many times,with delay between the openning and closing.Plus there is a bypass channel inside the EGR which also affects the temperature of the EGR.Originally the upper flex joint is designed to take all the flex,but the recall bracket may change the point where the expansion goes.
Your theory looks plausible too.Like most things in life it could be a mix of both factors.

Good thing is that me and the Norway tuner i am working with should be ready to offer some parts of that kind,along with software correction,for EGR and headache free motoring ;)

EGR block-off kit:
http://www.bimmertune.com/image/cach..._1-528x528.jpg

This is all great information, but I think this should have been followed by real readings using a dedicated BMW obdii reader,. What it is the temperature you are getting now for colant? What about the temperature of the coolant in the egr? How has the mileage improved if any?

In addition where is the sensor located that measures the coolant temperature? If it is on the other side of the line it may not confirm that the thermostat is bad.

That was a looooong quote ;)
There is a temperature sensor on the head and on the radiator outlet,standart for modern BMWs.Both values are under different names in the actual values menu,so it is not easy to mismatch them.

D5diesel - I don't have a dedicated BMW obd reader. I was using the "hidden menu" as described/referred to in my original post. For simplicity, you can see a PDF describing the hidden menu by copying and pasting the following link into your browser address (for some reason I can't make the link shortcut work for this):

http://www.scoopz.com/m5board/E60_Hi...structions.pdf

A link to a similar Bimmerfest posting is here (the PDF is from post #17):

X5 35d engine temperature - Bimmerfest - BMW Forums

The link says it is for an e60, but it works the same on my e70. As I mentioned in my original post, the pdf describes accessing the menu with the ignition on, but engine off. If one does this, though, one does not obtain information while the engine is operating (obviously). No problem, though, just access the menu the same way but with the engine on. To be specific, I monitored coolant temperature on menu 07.00 - as seen on page 12 of the PDF.

So my temps (from menu 07.00) went from 72-73 degrees Centigrade with highway mpg of 25-26 pre-repair, to temps of 84-85 Centigrade with highway mpg of 31-32 after the repair. This is with fairly cold temps in Atlanta recently (ambient temps 20-40 degrees Fahrenheit).

I don't know specifically where the sensor is located that gives the menu 07.00 temperature. I also don't know if there is a sensor that specifically gives EGR coolant temperature. Certainly I couldn't find such a temp in the PDF document noted above.

Hope the info above is helpful.

Subscribed....

The coolant temperature sensor is mounted on the intake side of the cylinder head. The coolant in the M57 flows through the thermostat to the exhaust side, over to the intake side and then out. The temperature shown in the hidden menue is from that sensor.

There is no EGR coolant temperature. There is however a sensor for the exhaust fumes after the high pressure EGR cooler. Our HP EGR has basically 2 tracks: part of the fumes always get cooled and part of the fumes go straight through. The DDE achieved the desired temperature by activating a valve that mixes the two in different ratios. I'm under the impression that there no such thing with the LP EGR since it's only activated once coolant temperature is above a certain temperature.

I believe the bypass in the HP EGR is there not so much to regulate temperature under regular driving condition but to facilitate warmup.

You can read more here, if interested: https://drive.google.com/file/d/0B1e...ew?usp=sharing

Hi, ZetaTre, could you specify the e-torx size you used for flange bolts.
What's the torch amount you used for different bolts?

Thanks

I don't remember what they are. I do have a set of Torx so I try them all out. I didn't really spec torqued them. I just went "gutten tight". Just link other things in life, lubrication is key: the flange bolts seize easily in the cast iron manifold so do a dry run before hand and coat them with anti-seize compound (the same used for spark plugs)

When you connecting the hoses back to the themostat and EGR, did you apply some silicone gasket or something to prevent anything leaking? Or just use those existing clamps would be enough? I'm a bit worried about that.

Thanks

I did because I have a habit of lubricating everything, but the connectors have a o-ring inside and they are generally not prone to leaks. Ensure the hose is properly seated and the metal clip is secured and you should be fine.

This is the lube I use on rubber seals and grommets: NAPA AUTO PARTS

One thing about the cooling system: part #1 in this diagram

http://www.realoem.com/bmw/diagrams/t/w/274.png

Is a rigid plastic tubing. You can flex it enough to connect it to the thermostat but it's a pretty scary thing. Consider releasing the bolt #2 holding it in place for simplicity. I believe I was able to reach to it under the EGR valve.

The diagram you posted is not showing up.
Could you just paste a link of it? Thanks

Sorry about that. The diagram is now a clickable link :)

You mentioned 2 flange bolts that are hidden underneath.
In this picture, you pointed one of it with a yellow arrow.
Could you point out where exactly is the other one? I made a Red circle on it, is it there?
Thanks

http://www.xoutpost.com/attachment.p...1&d=1422553200

scorpioy - Remember that (disregarding radiator hose and electrical sensor connections) the EGR cooler is held in place by a total of five connection points - the circumferential clamp (part #7 in the diagram below), two mounting bolts (locations shown by the two yellow arrows on the picture you reference, and one labeled as part #4 below), and by the two flange bolts (T-45) that connect the accordion end of the EGR cooler to the exhaust manifold. Here is a parts diagram of the EGR in situ:

http://www.realoem.com/bmw/diagrams/j/n/284.png http://www.realoem.com/bmw/images/diag_41jm.jpg

The diagram only shows one bolt for the top part of the flange (part #6). There is another bolt for the bottom of the flange. You can see that the flange and bolts connect the accordion end of the EGR cooler to the exhaust manifold. The insert diagram above shows the EGR cooler in yellow as it is positioned on the engine. To (hopefully) further clarify things, perhaps I confused you by saying that the red arrows pointed to two mounting bolts? I should have said that the arrows showed the mounting brackets that the mounting bolts go through. I'll edit my original post to make that more clear.

What you circled in red is one of the bolts that attach the EGR valve to the intake manifold. That bolt was never touched for the repair. For the sake of providing information, though, check out the diagram below. The EGR valve is part #1. It is mounted to the intake manifold by four bolts in essentially the four corners of a square. The diagram below shows a bolt (part #3) that fastens a bracket (part #7) and the EGR valve to the intake manifold via the "top driver's side bolt" location. The bolt you circled is not shown in the diagram, but would represent the "top passenger side" location. I may have made that more confusing with a lot of words - it's pretty obvious when you see it in front of you.

http://www.realoem.com/bmw/diagrams/r/d/525.png http://www.realoem.com/bmw/images/diag_7lgb.jpg

Hope that makes sense. If not, post a response and I think we'll eventually get it taken care of.

Regards

A Good Picture is worth a thousand words! Here is a picture from lpcapital (aka ZetaTre) from his bimmerfest post that got me started down this road (I referenced his post in my original post, but the link is here). Here you can clearly see that the flange at the accordion end of the EGR cooler has holes for the two flange bolts.

http://i259.photobucket.com/albums/h...110_194123.jpg


Hope that makes it clear.

Ok, I think I got it.
You were saying there is another flange bolt at the bottom. So I was think it's somewhere at the bottom of EGR, but it's just the bottom of flange itself. So two bolts on that single flange.
Thanks for such detailed explanation.

Could you provide me the realoem link of the first diagram in your last post?

I have ordered a new themostat from ebay. It's on its way.
I just have to build a solid plan in my head first for replacing it. That's why I got so many questions :)

Here is the link:

RealOEM.com * BMW E70 X5 3.5d pollutant reduction cooling

As I said in my post, I recommend the tight reach wrench (link is here) - it made it much easier to get to some of the bolts on the duct clamps.

Also, you might remember the electrical connector (for EGR temp sensor) that I said I had trouble disconnecting? Good to know I'm not alone. Check out posts #60 and 61 on this link - it's for a 335d, but the much of the info is relevant to our 35d. FWIW, I went back and tried the suggestion in post 61 of pulling the white tab all the way out, but I still couldn't get it to work. For me, using a very small flat blade screwdriver slid under the connector from the back side is still the best way to get it apart.

BTW, if you're replacing the thermostat I assume your temp is also not getting above 72-73 degrees?

Regards.

Yeh, my 09 3.5d shows 72 degree most of time, and barely reaching 74. That's why.
Thanks for the link.

bty, the way to unlock and show temperature on the dash is a bit annoy, it requires unlock each time... I was thinking once unlocked, it stays unlocked but my car's code is 26 and I need push 26 times every time...

This might be a good document to list the steps to remove the themostat

BMW Workshop Manuals > X Series E70 X5 3.0d (M57T2) OFFRD > 2 Repair Instructions > 11 Engine (M57T2) > 53 Thermostat And Connections > 1 RA Removing And Installing _ Replacing Coolant Thermostat (M57T2)

which means we don't have to deal with the hose to the right side of it.

I checked mine again and same thing, 74degC max. New T-stat is sitting in my garage but I am out in Whistler for the weekend :-), so will have to wait for another week to do the job.

Once in a while I also monitor my temperature and the EGT if it's regenerating using Torque app on my phone and a mini ELM OBD. I am getting a reading of 80°C-81°C even at freezing temps. And when it's regenerating EGT goes up to 600°C.

Ugh, Sunday morning, just opened the hood on the 35d and surveyed the plethora of parts needing to come off..... Another coffee before breaking out the wrenches seems justified :-)

Update: It is noon. Loosened the two bolts that are clearly one of the hardest to undo since they are tucked way back where the turbo seems to be or whatever that is. Took the two mounting bolts out of the EGR cooler. The electrical connection on the throttle body is indeed impossible to undo without sticking a small screw driver in there and wiggling it.

Got the cover off the bottom and drained coolant by disconnecting one of the two "mystery" hoses disapppearing into the driver's side fender. Apparently no drain plug at the bottom of the cooler as others have reported. Also disconnected the coolant connections to the EGR cooler and yes it is messy!

Not yet bothered with the fan shroud as so far I can tools in there easily enough. So far my knuckles are in tact... :-)

Next is disconnecting the EGR cooler from the throttle body. Sitting back with a coffee for now to contemplate and look at pictures earlier in this thread. I just remind myself of the avoided cost to keep motivated.....

back together and running 86 -89 c
 

It is back together and test drove it. The wonderful BMW people wanted to do all kind of test programs and charge me close to a thousand to replace it....I am switching dealerships for service as the place I previously went lost its service manager and the current one is....shall we say: NOT very good....

Only thing to add are a few pics and a couple of pointers.

I covered the intake to the turbo with a cup lid from a Starbucks cup. That opening is just perfect to drop something in it while you are wrenching!

The tabs on the fan shroud are held in by clips, you have to press the top and pull up a little until both are free. The drivers' side flips inward to clear the top hose on the radiator.

Many thanks to all for good pictures and descriptions, it made it a lot less scary.

^ Congrats.

Sounds like a "4 coffee job"?

;)

Or 3 coffee and a beer, weather dependant ;)

Woot, Woot!

Congrats and Well Done!

Stephen

Thanks guys.

Unfortunately no beer....but 4 venti-sized coffees yes. Nevertheless, now that I have been in there and "mentally cataloged" the procedure I could repeat it in half the time. Putting it back together and testing, then reattaching the bottom engine cover took about 1.5 hours.

If one is doing this in a fully equipped shop this should be no more then 2 hours in all. Not sure where the 1000 dollar quote came from other than an unreliable Service manager.

Since you're where it's very cold these days, you're feedback on the engine temperature would be extremely valuable. Let us know!!!

It is my wife's daily driver but I will try to get some seat time and let you know. Yesterday it zipped right up to 87-89 on a short 1 mile trip to the Giant.

Can I pick your brains please gents gents?

I have a UK spec, X5 E70 35d, 2009 build, 2010 registered car with about 40k miles on it.

At the moment ambient temp here is about 8C.

I have a Scangauge permanently connected to my OBD port and mounted on the dash so I can monitor engine temp and battery voltage.

When fully warm my engine temp runs at 84c +/-2degrees. At this time of the year getting fully warm takes a while, up to 5 miles on slow country roads, quicker if the starting ambient temp is less than 5C and the Webasto FBH comes on.

Now here is my question; if, fully warmed up, I cruse at say 50 MPH on a dual carriageway with temp showing 84C and then floor the throttle and let the box change down a couple of gears and let the revs climb towards max RPM, the temp immediately drops to around 75C, then as soon as I lift off and continue normal driving it returns to 85C with in 10 seconds or so. This is RPM related and not road speed related.

Seems strange to me, am I missing something?

BTW the car runs fine and shows no codes and returns reasonable fuel economy.

-10 Celsius ambient last night. On Interstate at steady 65mph speed mine runs 83-84 C.

[ Snow coming down hard today. Very happy with winter tires on both X5s right now.... :-) ]

Most likely when you open up the throttle, the throttle body throws in a lot of colder air and that is the reason for the temperature drop. However, if you stayed on it for a while it would start to heat up and probably surpass your cruising temps.

-11 to -18C outside today and I was running a solid 82 to 83C at highway speeds. I am very glad I put dedicated snow tires on the X5 this winter. I experienced DEF freeze for the first time this morning; it was -18.5C when I started her up according to the ambient temperature sensor.

Curious, how do you know the DEF was frozen?

I park indoor (garage is part of the house) so I haven't experienced that yet.

Thanks but I suspect the drop is too quick for that as it happens in seconds and I would have thought it would have taken longer for intake air to effect the water jacket especially in relatively mild weather. But who knows.

I'm going to change the ecg stat today as its a cheap and easy job and see if that helps

Yeah, those are too quick changes in the temp to be real. 75 to 85 in 10 secs while cruising on the motorway is unlikely to happen even in a hot summer day.

OK changed the EGR stat and it makes no difference.

I did a quick test; sitting stationary with a full heat soaked engine, RPM at idle, temp 84c. Increase RPM to 4000 and temp drops to 71c in 6 seconds. Drop RPM back to idle and temp returns to 84 in 20 seconds. ??

Same test but increasing RPM to 2200 shows no drop ???

The check engine light came on. I used BMWhat and read the DTC which was "Reductant pressure control, plausibility Code: 4952".

I assume because it was frozen, it could not supply the proper pressure. After about 30 minutes of driving, I reset it and it didn't come on again over the next three hours or so I was driving. That combined with the fact that it was well below the -11C freeze point of the DEF solution and that the X5 was sitting in -10.5C to -18C temperatures for over 15 hours. I suppose I can't know for sure.

ERG thermostat? I think this thread is about COOLANT thermostat and how low it gets stuck in open position and results in lower engine coolant temperature and thus worse gas mileage.

Non US cars have 2 coolant thermostat: the main one and then one on the coolant line that runs through the EGR cooler. That one too fails.

To London Lad: the first thing I would confirm is that your particular engine doe not have a map controlled thermostat. I don't think any diesel engine does, but I would double check. The easiest way is probably too loop up RealOEM with your VIN and see if the thermostat has any wiring going to it. That is unless you can see the thermostat casing. Map controlled thermostat have an electrical heating element controlled by the ECU that opens the thermostat under certain conditions. It is very common in gasoline cars where the engine normally runs at higher temperature while cursing (to increase fuel economy) while cooler under acceleration.

If you have a regular thermostat than it a puzzling behavior: perhaps the thermostat has weaken to the point that the increased flow from the faster spinning water pump opens it? It is not a normal behavior and the temperature of the air coming into the intake has no effect...

To ZetaTre

Thanks for that. I had been starting to think that a weak stat spring giving way under pump pressure was the only explanation. Its not MAP controlled. I have experienced them failing (the heater part) in new Minis before

But how in the world this engine will loose 13C in 6 seconds and heat-up 13C in 20 seconds on idle? Are you sure you are looking at the coolant sensor data and not the radiator outlet temp?

I'm using THIS which only has one water temp gauge ?

Almost looks like intake temperature or something.


I have two of these. Unfortunately it's not with me right now so I can't see how it works on the X5. Works good on my Tahoe and M5.

I'd like to report back after replacing the themostat. Now the temp is around 89-90 degree most of time.
Thanks to ZetaTre and rest of people helped.

My Z4 has a map controlled thermostat. When you stomp on the gas the coolant temperature drops extremely quickly and when the pedal is released jumps back almost as quickly. We are talking 4/5 secs to shave almost 20 degrees celsius.

At cruising the thermostat is barely open to maintain operating temperature, particularly in a diesel that generates little heat and with the massive radiator that the X5 has. If it opens all the way, for example because the spring can't hold the increased coolant flow the temperature will tank. That's why I took that swag about the thermostat opening up...

I suspect you are correct. I will enable the hidden menu water temp read out (if I can find the info and understand it!) just in case my scan gauge is reading the wrong temp for some reason but I don't think it is.

All gasoline BMWs after 1999 or so have electronically controlled thermostat. But what you wrote doesnt add up. When you LEFT OFF the gas the temp is raising 20C :yikes: From where the heat will come if the engine is not loaded? And even more so not loaded diesel in a cold weather.

I was simply using the example of my Z4 which has a 2.5l gasoline engine and an electronic controlled thermostat as an observation of how quickly the temperature can change in the engine when the thermostat is open very quickly (and conversely shuts quickly when the ECU stops manipulating it)... I really didn't want to sidetrack the discussion, just drawing a parallel to what appears to be a odd behavior that London Lad reported.

If it's not the thermostat, then what's not working right?

To warm engine or water 20C you need to take energy from somewhere. In the case of idling diesel this energy is just not there. A 6 cylinder engine full of 3 gallons coolant has a huge thermal inertia and this kind of fast warm-ups and cool downs are not plausible. My opinion is that "London Lad" is getting a false reading due to the tool that he is using or due to electronic problem in his car.

OK well I have checked the reading against the dash hidden obd and another obd hand-held and the results are the same. Its as if the increased RPM forces the stat open and allows a large inrush of cold water. Running at 70 mph at light load, drop 2 gears and floor it, temp drops 15C in 5 to 8 seconds. Lift off and drop back to normal 'drive auto' and the lost temp rebuilds in about 20 seconds. All other temp readings during warm up etc look normal. No OBD fault codes are being logged.

:popcorn::popcorn:

I got my thermostat replaced. On its first or second day, the temp stays around 89-90 degree most of time. Then the following days, it varies from 65-80 on highway, 84-94 on local. Outside temp is about -10 degree these days.

Is this normal? Do you guys have a steady 88 degree most of time?
I purchased thermostat from ebay with under $40. My local dealer asks more than $150.
Where do you guys buy it from?
I doubt the one I bought does not have a good quality...

Thanks.

$150? Wow.
My local dealer quoted $90. Assuming OEM (is OEM even a good thing anymore?).

ZetaTre/lcapital,
Is the temperature on yours still happily 89-91 since t-stat replacement?

Mi wife drives the X5 so I don't monitor it on a daily basis, but whenever I drive it, the temperature is constant in the operating range. I'll ask her if she lets me drive it for a couple of days and I do some logging, including see if it holds temp when you floor it.

HOWEVER my dad is back at having longer warmups after about 70K km (45K miles). He had the dealer in Italy warranty the old one and now has to replace it again. We live up in the Alps and he said that no matter what was the outside temperature the car would get and stay in the operating range, but not recently and again while cruising at 70 mph on a flat he still sees the temp dropping below 80/75.

We'll see when he replaces it again if things get restored, but if that's the case, these thermostats are pretty much cacca

And by the way people, the MSRP of the thermostat is $79.05 so don't get stiffed by your dealer... Granted they shouldn't be jacking up price 2 fold, but for the love of God, think with your head not your wallet... Seriously...

I can only tell you that even in temperatures as low as -19C, coolant temperature was 83-84C on the highway once the engine was fully warmed up. On shorter trips and in -15C, coolant temperature was 81-82C but would dip down to 79 or 78C if load came off. Temperature drops pretty quickly at idle. I haven't had any experience in warmer ambient temperatures to know what coolant temperature runs in those conditions.

So I think I'm screwed up by this counterfeit t-stat. I need buy a new one again.
Do you guys go to dealers or is there a good aftermarket ones I can buy from some website?

Thanks

There are dealers that offer discounted prices online. You are better off using a BMW thermostat as BMW parts come with a 2-year warranty.

Actually any part not installed from an authorized dealer has no warranty. Any car manufacturer.

This is the first time I hear this and this official BMW page actually says it comes with 2 year unlimited mileage warranty with no fine prints or statement about only is installed by an authorized dealer: BMW Center Services - Overview - BMW North America

Now, from a practical level, they may pull the card of not being properly installed, but that's different than saying there's no warranty.

And btw, I'm sorry about this; I'm really not trying to pick on you...

No problem. From what I know any warranty on any part requires instalation in an authorized dealer. That is 100% true for any electric or electronic part. Once you take it out of the dealer uninstalled, it is yours forever. I didnt really think about a T-stat, but I cant imagine you will buy a water pump or transmission and you will go back after 23 months and get any kind of warranty, or even a discount on a replacement part.

On the topic of the transmission cooler thermostat, has anybody ever noticed or had a failure of that part?

I am as big a fan of unnecessary preventative maintenance as the next guy, but something like this seems like maybe you don't want to mess with it unless you have to. Especially because I can't see how a slightly cooler than normal transmission could have any ill-effects (based on nothing but my understanding of how cars work. Perhaps the ATF does require a small temperature range for optimal performance and minimal breakdown?)

Not correct. BMW's parts warranty is 2 years unlimited mileage providing the part was purchased from an authorized BMW dealer. It does not matter who does the installation thought I am sure anything obviously cocked up would be excluded. Labor for the warranty repair is covered if it is performed at a authorized BMW center. All is explained in SI B01 01 14.

Cheers.

Funny you should mention this... The bigger concern with the transmission cooler thermostat is (if I am reading the hose diagrams correctly) that if it fails open it will allow coolant to flow through the radiator and back into the engine - bypassing the main thermostat.

I recently had the main thermostat replaced (after arguing with the dealer for two weeks that it was bad - "can't be bad if there are no codes...") and immediately our temperatures went from 65-70C to 89-91C. This was in a Chicago winter and I was monitoring it one day with ambient at 4F and driving on the interstate it stayed steady at 89-91C (it would go a few degrees higher during DPF regen). We are now a few months later and the temperature has dropped to ~84C while cruising on the highway. In town it will creep up to around 90C. Theses are the classic signs to me that coolant is prematurely passing through the radiator. My next step is to replace the transmission cooler thermostat.

There have been many posts in this thread asking what the proper coolant temp is. Since these engines use an old school thermostat that is designed to begin to open at 88C the proper temps to look for are slightly above that - i.e. 89-91C. Anything less than that is an indication that "cooled coolant" is being sent to the engine before it is warranted and you have a failed or failing thermostat. Then the question becomes: "which one?"

Cheers.

BMW Service : Warranties

Original BMW Parts as well as Original BMW Accessories, a warranty of two years regardless of the mileage is offered. Service you can count on - we guarantee it.

Original BMW Parts : Remanufactured Parts

Yet every exchangeable part is subject to exactly the same quality specifications as a new BMW Part and it even carries the same 24-month warranty.

Neither mention the requirement that an authorized repair facility needs to do the installation. BMW does cover the labor of the installation of the part for 2 years if performed at a BMW dealer though.

So, if a dealer installs a part, the part and labor are covered for 2 years. If you or a non-dealer installs it, just the part is covered. If an indy did the install, they might warranty their own work though.

If you buy BMW floor mats and don't have the dealer install them, are you saying they wouldn't be covered?

If you bought a transmission and didn't have the dealer install but 1 year later first gear went out, you don't think BMW would honor the warranty if it was installed in a BMW? Wouldn't the Magnuson–Moss act come into play?

I know nothing about Magnusson-Moss act, but i dare you to try. I can assure you there is not 1 hour warranty or return options for electronic parts if you take it out of the dealer not installed. There are a lot of electronic parts in the transmission, so in a case of failure it could swing either way. BMW will claim it was programmed incorrectly when first installed and nor Magnusson neither Moss could prove the opposite.
Everyone is free to believe what he wants, i just like to warn you that these are not all unconditional warranties.

Then why make such profound statements?

Please provide proof of your assurance.

How do you know, above you stated that you know nothing of the Magnusson-Moss act.

QUOTE]Everyone is free to believe what he wants, i just like to warn you that these are not all unconditional warranties.[/QUOTE]

How it it a warning when you first state that you know nothing of the Magnusson-Moss act. Then you say that you can assure that there is no warranty at all on electronic parts if the dealer doesn't install them but provided absolutely no proof at all. Before you were stating that BMW parts had no warranty unless installed by the dealer, which has been proven false.

Actually, the only reason why I threw the transmission heat exchanger thermostat in the mix it is simply because it is a similar design as the one on the EU version of the EGR cooler (which is prone to failure) and because BMW is generally challenged with thermostats.

But in any case, if you do go ahead and replace it, let us know how it turns out.

So for those of you who have had your X5s a while, what would you consider poor fuel economy?

I noticed, based on my gauge, over about 50 miles worth of mostly highway, that I was only averaging low to mid 23s. At one point it was up to 24.1 but as the highway turned a little more uphill it dropped back to the low 23s. I may have mentioned already that I've monitored my coolant temp and it never eclipses 80C, but I wasn't sure if that was cold enough to really effect fuel economy.

On the bright side, when I'm commuting, and thus sitting in lots of traffic, my mileage is right around 22, so it's not a lot worse than my highway mileage.

^^This my experience mostly. 23-25 mpg @75-80mph.
I have a feeling that the sport package 20" wheels cost 1-3 mpg.

Gotcha. I have the sport package with 19" wheels, but yes, I was also cruising around 70-75mph

Finally got around to doing this. Thank you, BMW, for making a simple thermostat a 4 hour job :|

Anyway, the process wasn't overly complex. I tried harder to find a large coolant line than I needed to, so that was wasted time. Then I found I took more of the intake off than was necessary, which also wasted time.

Note to those thinking about it. Those two flange bolts for the EGT cooler really are as tricky as you have read. Be careful and good luck. Also, the transmission cooling thermostat is SO easy to replace once you're in there, so cough up the extra $80 for that part and just do it to be safe. Once the fan is out, 3 10mm bolts and a clipped in line is all you have to replace.

I'd rather the thread stay on topic... but I think the attached document is of some value to the DIY person... and I'm not on the forums often.
I bought a BMW battery over the counter at one Dealer, installed and registered myself. 2 years later it would not hold a charge. I drove the BMW to a different dealer, handed them a copy of the parts invoice and the attached Parts Warranty. They performed diagnotics, installed a new battery, registered it and I walked out with no bill. So Parts and Labor were covered on a part I bought and installed. It's possible this would have occured without the attached PDF, but I doubt it.

Note the language of "date of sale or installation". Good luck!

Just wanted to bump up the thread with my story.

I decided to test this out myself.

Outside temp was 6degrees celcius
I drove about 30 minutes before doing the test, so it was on a warm motor. It started off at 71 then slowly climbed to 88-89 (took about 15 minutes of idling)

Then I drove onto the freeway for about 20 minutes with the cruise on 110km/h (68 mph)

The temps immediately dropped down to 70-71.
I just ordered a new t-stat, and so it'll probably get done sometime later this week. I'll update the thread again with my findings.

Current fuel mileage (according to my cluster) 8.6L/100 (~27.35 US MPG)
20" Nurburgring RF wheels

Look around for a post from ninja_zx10 on the proper tightening sequence of the EGR cooler. Make sure you follow it.

I'd also suggest you put some anti-seize on the bolts and the mating surface on the exhaust manifold side of the EGR cooler to ensure the bolts don't get stuck in the cast iron. In my case I put the anti-seize on the bolts, drove them through first and then recoat them before installing the cooler.

You don't need to disconnect any of the vacuum lines on the EGR cooler. You can simply flip it up and out of the way.

http://i259.photobucket.com/albums/h...110_194123.jpg

One side of the thermostat connects to a rigid line that goes towards the driver side around the head and under the throttle valve. There is bolt under the throttle valve that hold that line. It may help to release that bolt to get a bit more slack out of the rigid line.

Some of these things may not make lots of sense now, but keep them in mind as they will become clear once you're in there.

I saw that post yesterday while I was reading the thread of the guy who went through 5 EGRs due to cracking. Thanks, i'll make sure to check it out.

While I'm in there, is there anything else you think I should replace? I remember on my 335, the water pump (electric) had to be replaced. Any known issues with them? (its only 3 more bolts to remove the water pump)

For anyone else reading this thread, here are the torque specs, and the EGR Cooler installation instructions with the tightening sequence.

Just an update. I just realized I was reading my cluster wrong. I'm actually getting 12L/100km (19mpg) so now I'm really looking forward to see if this helps with mileage

FWIW, soft thermostats are not uncommon among the German car manufacturers. I believe the problem is with the main spring tempering or maybe lack of.

I see this exact same problem on the I6 gasoline engines as well. You cannot easily flag a soft thermostat until the ambient temps drop below 70F and get the vehicle cruising above 40 MPH constantly.

Best to baseline/benchmark the engine coolant temps and then carefully monitor the engine coolant temperature before the hard Winter temps settle in.

I'm going to replace mine. I'm waiting for the part to arrive (should have been today, hopefully tomorrow) Our winters get pretty cold (-30c plus windchill at times)

Based on recommendations here, I will monitor the temps on my X5 but will already order both thermostats, just to be ready.

Another point of reference that others should gather is what is the "nominal" engine temperature on these Diesels.

So if the thermostat states say 89C this does not necessarily mean the engine will run at 89C. The displayed operational engine temperature depends on where the coolant temperature sensor is located.

On many gasoline engines with the temperature sender located in the water output path of the cylinder head actually register about 15F /9C higher than the thermostat operating temperature.

So it would be helpful for anyone that installs a new thermostat to note what the "nominal" engine operating temperature is around 70F ambient or lower.

Mine settled out at 95c when fully warm after new main and EGR stats were fitted

Seems that most modern engines tend to run around 205F/96C except for the N62 which seems to run around 226F/108C!!!

Can you confirm if the thermostat for the Diesel is labeled with 88C like the one in the beginning of the thread? I believe even if the thermostat is labeled as 88C then this is typical that the engine temperature is actually operating about 15F/9C higher than the thermostat operating temperature.

Yes.

Prior to the new stat i was running at a MAX of 84c and it took longer to get there. since the new stat I seem to be getting 2-3 more miles per (UK) gallon

Thanks for confirming the value stamped on the stat. This can often be misleading because SO MANY people think the engine is supposed to operate at the stat temp which is RARELY the case. Except for M vehicles, most engines operate in the 205F/96C range. When the engine runs cool, fuel consumption increases and oil contaminates quicker.

I ordered the main thermostat from AutohausAZ and the transmission cooler thermostat with GetBMWParts. AutohausAZ doesn't carry the transmission cooler thermostat. I will check the temps today more thoroughly as yesterday after the wife came home I checked the temp and it never went up above 72 and played between 68 and maxed out at 72.

Has anyone had this thermostat fail the opposite way (completely shut)? This seems to be the issues we deal with in the gas engines. I have had a number of cars have this issue but never running colder than spec.

Most modern thermostats go soft and run too cold. The main springs get weak over time, sometimes in less than 2 years.

Get OBDFusion for your phone/tablet and the proper interface (usually less than $20) and you can easily monitor AND Log the temps and other values.

Don't forget that there is (dependant on engine) an EGR cooler stat too and that can fail

I understand in this particular instance the spring is not strong enough to close the flow. I am understanding the meaning of a "modern" thermostat as the issue of a failed thermostat in a gas engine is commonplace even at this time. I have an 08 535xi wagon where I just replaced the thermostat for that very reason.
My question was, are there folks who have had issues with a closed thermostat that leads to overheating?

I finally got to monitor the coolant temperature in the X5 this morning. The run to wife's office with the AC on at 16 deg C outside temperature never went above 72 deg C.

On my way to my office, I turned off the AC and the highest the temp got was while I was idling for a few minutes at a stoplight. It went up to 84 deg C but went down after the stop light and settled at around 72 deg C on the freeway.

With my wife driving, it never left 72 deg and would go back and forth between 68 to 72. So definitely needing a thermostat replacement.

It's a good thing, I have placed the order for the two thermostats.

The problem is not that the spring is not strong enough to close the thermostat properly, the problem is the preload on the spring is not strong enough therefore allowing the thermostat to start to open too early.

As for thermostats stuck closed, it rarely happens based on the design. Most overheating problems these days are due to low coolant/coolant leaks. Low coolant can cause the thermostat to not open due to no warm coolant for the thermostat to react to.

Finally got around to replacing the thermostats. I followed the advise here and replaced both the radiator and oil cooler thermostats. After going around 3 miles the temperature now reads 87 degrees.

I'm wondering what the consensus is on what exactly constitutes a 'bad' thermostat. I monitored the coolant temps on my wife's X5 while towing a trailer in a mix of city and highway driving, with outdoor temps at 40F. The temps were pretty consistent between 79 -82C...certainly not as low as some here are experiencing. I have a new thermostat on the way and I'll probably install it anyway just to get ahead of when the original unit does eventually fail, but I'm almost thinking that it might be OK for now.

You are getting to 82 because you are towing. The only time I got there was when I turned off the AC which turns off the fan (until it needs it) and I ws idling for a couple of minutes at a stop light. After which it went back to 72.

As mentioned in previous posts, if the thermostat doesn't keep the temp at 88 or so degrees, the glow plugs turn on to keep it at that temperature and the DPF does not regenerate. If this continues, the glow plugs will eventually burn itself out and the DPF will clog.

The worst issue with a thermostat is if fails at the closed position making the car overheat. This was the question, I was asking earlier, Has anyone had a thermostat fail in the closed position and having overheated the motor?

Either way, both issues require attention.

Pretty much what I figured. I'll replace it next week and report back :thumbup:

Just want to report back that I replaced the thermostat today and am now running at a consistent 188-190F, or 88C. Thanks to everyone here the whole process really wasn't that bad. If I were to do it over, I could probably do it in under 3 hours. I did wind up with a coolant leak from a hose off the new Tstat and had to dive back in to refasten it, but it wasn't actually a huge deal. :cool:

I just change my thermostat at only 39k miles on my 09. So this is more of an age thing than a mileage thing. My old thermostat had good days and bad days. A bad one would be stuck around 75 degrees and a good one would stick at 83. So don't monitor for one trip and assume you are good or bad. I am in FL and it is still in the 70s here so my bad low reading would probably be lower if I lived in a normal part of the country.

Just completed a thermostat replacement on my 2010. Was regulating to about 72DegC(161DegF). Nice boost in mileage of about 2 L/100Km after 1st tank city & hwy.

FYI, I did not remove my fan to replace the thermostat.

Removing the top reinforcement bar and the fan is the easiest thing to do. The fan housing has a foldable tab on one side so it slides up in just seconds.

Wow!How did you do that without removing the fan? That area is so tight.Did you reach out the thermostat from the bottom side?did you remove the egr cooler?

Yes it does make a difference in fuel economy especially if your old one was maintaining under 75 deg C.It's because engine remains in a Rapid warm up phase and injects more diesel until it reaches normal operating temperature.That's what I read in BMW technical documents.

Got in there with various deep sockets and/or short extensions. Had enough room to fit my air ratchet in there although that isn't required for the job. Just speeds up the process.

EGR cooler comes out first then I removed the thermostat from the top.

Were you able to replace the oil cooler thermostat without removing the radiator &/or fan shroud?

Well done. All of you BMW diesel drivers should check the thermostat and the glow plugs. You can end up like this one if you drive aroung with cold engine :(

http://www2.pic-upload.de/img/29310537/IMG_1861.jpg

http://www2.pic-upload.de/img/29310546/IMG_2148.jpg

http://www2.pic-upload.de/img/29310545/IMG_2131.jpg
https://yadi.sk/i/YDAdKZZfmeKhQ

Melted piston!!!?!!?! Was that a leaky injector? What makes you link it to a thermostat?

Sent from my Nexus 5X using Tapatalk

I can not tell for sure but i think it could be a part of the reason why it happened. The injector of this cylinder was destroyed. No chance to check if it was defective.

Help me understand what's the link because I'm not sure I follow.

Hmmm... I have an '11 35d with about 78k I just bought a couple months ago. So far it's been averaging 17.5mpg with about 85% city driving. I would have thought it be a little higher. But not sure about what temp it's running at, will have to look into that. But does that sound like a reasonable mpg I should expect?

Picking up the parts to do my water pump, thermostat, AC and auxiliary belt tomorrow. Also grabbing the exhaust back pressure sensor (been getting code 4D03 sporadically on longer drives).

Someone also mentioned doing the cooler thermostat. Anyone know the part number for that one? Thinking of doing the expansion tank as well.

That seems very low. I have a 2011 35d and i drive mostly city/some hywy and i average 25mpg

I'm definitely going to look into this. How many miles on yours?

110k~
Get OBDfusion app and a CAS bluetooth dongle, you will be able to see temps and do many other diagnostic procedures.

Transmission oil cooler thermostat for E70 35D part no:17107558267


RealOEM.com - Online BMW Parts Catalog

Wow, more than mine. Did you have your thermostat done already?

looks like a big job to do the thermostat. Anyone know what the labor time should be?

Nope, as far as i know mine is stock and temps are around 84c degrees

Go figure. some people complaining at 60-70k miles and others dont have any issues well over 100k. :dunno:

Thanks to the OP and everyone who posted to this thread. We just picked up a 2010 35D and I immediately checked for this issue. Even with extended driving, the temps never get above 71deg C. As the car is in California and under the 70k extended emissions threshold, I took it to the dealership to get checked out. While they found some other faults with the SCR system and replaced those already, it seems they are dragging their feet on the thermostat. They claim "these diesels take a long time to warm up" etc. Can anyone point me to official factory tech specs that indicate what the normal operating temp is supposed to be? I've searched a number of threads and have only been able to find people using the 88deg C marking on the thermostat as "proof." Anything that will help me "educate" the dealership would be great!

I managed to catch a regen while driving today. Got some data from BMWhat. I have a question about regenerations in this car. I see a lot of people saying that regeneration won't occur if the car doesn't get to 75C...the whole active vs. passive. My engine coolant rarely gets above 71C...but I still get pretty consistent regens according to the data. Today it was 25F (-4C) outside.

My car average regeneration is 444KM or 275 miles. Today it occurred at 400,000 meters or 250 miles. The car was definitely not running very hard and was only running for 30 minutes around town errands (30-50mph roads, not much stopping). But I did see the temps go up, car mpg dropped considerably, and soot level (in grams) started to drop as regeneration kicked in.

Soot mass was 3.74 grams when regeneration started. Engine temp was 71C, and went up and stayed at 76C for about 15 minutes of 30-55mph driving. Once regeneration was complete temp dropped to 71C.

Maybe my car is an anomaly (knock on wood)? Anyone else not having regen problems with high mileage X5s?

The minimum threshold for regeneration is 60℃ not 75℃ and if coolant temperature remains below 60℃ then it would throw thermostat malfunction code.

Here is the technical literature on BMW's that I know of. It's about a thousand pages without much organization and no index. Descriptions of the diesel engine's starting sequences imply some NOT as being when adjustments for starting are terminated. I do not recall a positive statement of normal operating temperature.

https://drive.google.com/folderview?...&usp=drive_web

https://drive.google.com/folderview?...&usp=drive_web

MCPOCG Al Thiele BMCM is neighbor.

Air circulation engine code is up
 

So I did all this work on main this week and the only thing didn't change from before is the smell. Main is a diesel and I get the smoke smell inside the cabin and The shop told me I'm getting smell inside my cabin because of the egr cooler Leake but I replaced with a new one and I'm still getting a bit smell. I have no clue where that's coming from. I also changed the thermostat once the egr cooler being replaced. Now my worries are how do I get the codes off. I was expecting to go off automatically but I don't know if that's possible. Can someone tell me what else is the parts i can check to change the smell.

Thanks for the link! I've used some of the items in there to support my case, but I fear it may be a lost cause. I'm going to try and present a temp log to the SA, but it seems their position is: No Code, No Problem.

I bet the Master Chief has some pretty amazing stories. It was a very different service back then! As a prior BM myself, glad to serve in his legacy.

Beemerboie - Exhaust smell in the cabin is getting a bit off topic from thermostat function, so further lengthy discussion would probably be best on a different posting. Nonetheless, though, I would say that if your EGR cooler is OK, then look at these 2 posts for further possibilities.

The first link is here, and I particularly recommend looking at post #9 with the melted exhaust gas pressure line. I seem to recall some other posts about other exhaust gas pressure sensor lines coming loose near the dpf, but I can't find those at this time.

The second link is here, and details what I found in my car (I post as stevieg on bimmerfest). Be aware that no disassembly is required to look at the two bolts that loosened up/fell out on my upper/small/high pressure turbo. Pop the hood and look on the passenger side (US car) and make sure there's no soot on the side of the upper turbo, and look in the gap between the heat shield and the turbo to make sure your bolts are in place. You'll only be able to see two of the three bolts without removing or loosening the heat shield, but between the presence/absence of soot and the two bolts - that should be enough to see if a leaky turbo is the source of the smell.

Hope that helps.

Thanks a lot for the reply with the links it actually helped me I'm gona try once I get a time. @sgrice

So just a quick update. After providing data logs / graphs to Weatherford BMW service showing temps that never got above 169F/72C, the SA is refusing to warranty the thermostat under CA supplemental warranty. He claims that the only way to do warranty work is to have a code! What's so frustrating is that he stated normal temp should be between "190-200F" but won't do anything about it. I've fired off a response to him and his managers, but I doubt they will do anything. In the end, I'm capable enough to do the repair myself, but the principle of the matter still grates at me! I'll report back when complete.

I just wanted to say THANK YOU!. have been noticing lower mpg as well so i checked and the engine never got above 77c and thats while it was 20f outside. I replaced the thermo and boom, back at 88c and up 3-4 mpg!

Do say that, ever... You don't want to jinx it... :thumbup::thumbup::thumbup:

Ha, very good point!

Thanks so much to sgrice and all that contributed on this thread! I am about to embark on replacing the thermostat and water pump. SO HELP ME GOD =) Sorry if I couldn't seem to find it.. but does anyone know the proper torque value for the water pump and thermostat? Thanks

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diegoX: It is interesting that I was never able to find a torque value for the thermostat. If you look at the link in post #34 of this thread you will see no torque value at all. Nonetheless, I looked around at some other threads and 10Nm was listed, and that is what I used. Not very tight, but there is a rubber gasket, and you don't want to crack the plastic housing. No leaks for me with 10 Nm.

For the water pump to crankcase bolts, I found a tightening spec of 10Nm if you have a M6 thread, 15 NM for a M7 thread, and 22 Nm for an M8 thread. In my car (and I suspect your car as well), I had an M7 bolt, and thus used 15 NM.

A couple of things to keep in mind:

1) If you're replacing the water pump as well, I'm pretty sure you will need to loosen/remove a bolt under the throttle valve that holds in place the hard return pipe from the water pump. Check out this RealOEM link. So the hard return pipe (part #1) is held in place by a 10 mm bolt under the throttle valve right around the area where part # 2 or 3 is shown. You'll need to remove that bolt in order to have enough wiggle room to get the water pump disconnected from the hard pipe.

2) I assume you will be replacing the metal water pump gasket. Be aware the original metal gasket was put in place during engine assembly with the use of metal tabs that locked the gasket in place prior to adding the water pump. Those three metal tabs will need to be cut in order to get the old metal gasket out. It's fairly thin metal (about the thickness of a soda can), so it's not hard to cut. Assuming you will use something like a sharp metal chisel to cut the tab - make sure the cut is made away from the mating surface. Don't scratch up the mating surface.

3) I'm sure you've seen it mentioned, but make sure you follow the EGR tightening protocol and torque values so that you don't end up with a cracked EGR cooler. Post #92 has a link to the appropriate pdfs.

Hope that helps. Good luck. Take it slowly and you'll be fine. A few tricky aspects, but once it's done I hope you'll agree it's not really that bad!

Stephen

Hi Stephen! Yes I have the water pump gasket too. It should be fine using a little sealant to keep it in place right? Thanks for the heads up on those metal tabs. Ready to flush the coolant but FedEx says delay on the tite-reach wrench I ordered to make my life a bit easier. Couldn't find an alternative tool like it in those big stores around here. Thanks so much

Just to give you a bit of extra info, attached are some pdf documents from Rheingold. I got Rheingold after I had already done the repair myself. Between the attachments here and the discussion points in the thread, you should be in good shape.

People frequently debate whether or not to add gasket sealants. I did not, and have not had any problems. I suspect a modest amount of appropriate sealant would be fine, but have no experience.

Attachment 69062

Attachment 69063

Attachment 69064

Attachment 69065

Attachment 69066

This is absolutely helpful! Thanks!

Sgrice, did you remove this electrical part pointed below to get to the egr cooler T45 screws? Just checking if there's an easier way to take this off. Retainer springs were removed and yet seems hard to pull out.

http://i27.photobucket.com/albums/c1...psdeloeszf.jpg

No, that is the CCV hose with the electrical connector for the heater element (a convoluted wiring).

It doesn't get removed to get to the EGR cooler bolts.

copy that, thanks!

You can remove it to gain more room, but not nesicary. The lower end goes onto the plastic inlet tube to the turbo. And the top has 2 push spring connectors. The plastic intake pipe is held on by one bolt so it's pretty quick to remove together. Mine has lots of cracks and needed to be replace.
https://c1552172.ssl.cf0.rackcdn.com/626341_x800.jpg

Thanks for the info sir. I ended not removing it after one of the push spring connectors fell into the abyss never to be found again which pretty much the only major frustration wasting time looking for it. LOL Hopefully i can purchase such pin somewhere.

Should have ordered and replaced the belts at the same time.!ouch:

Sorry for my tardy response - I've been out of town. But the responses from ZetaTre and boredincl are totally correct: Not necessary to remove, but if removed will give you better access. Doubt you can get a push connector separately, but the whole part (as shown by boredincl) is less expensive that one might think (I seem to recall something on the order of $60, but I can't find it on Realoem right now).

Hope the rest of the job went well. Be sure to post any thoughts you might have which might it easier for the next person.

Stephen

Taking me longer than usual because of work. Pump and thermostat are out and decided to remove/ clean the intake valve and egr valve (do you know the torques on those too? :D). Having issues cutting out those "metal tabs" you mentioned that came with OEM water pump gasket. I don't have the cross cut chisel, tried a screw driver to no avail. maybe I'm just too careful. Limited space to swing the hammer. I might have to get that chisel tomorrow.

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http://i27.photobucket.com/albums/c1...pswzhkbrxp.jpg

egr valve
http://i27.photobucket.com/albums/c1...ps78tnbwix.jpg

intake valve
http://i27.photobucket.com/albums/c1...pslmmuksge.jpg

egr valve electrical connection is hard to undo at least for me. The white tab won't snap out despite prying with screw driver.
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Amen about the egr electrical connection. I think I mentioned it in the first post, and it was mentioned again in one of the later posts - but it is difficult. It's hard to describe the technique, but it's not so much "prying" with a micro-screwdriver, as it is sliding it between the two parts of the connector. There is some sort of a internal "ramp" that the clip catches on. I put the micro-screwdriver flat blade inbetween the two connector parts (from the back side), slide it back and forth for about 30 seconds while pulling with moderate force, and then suddenly the connector separates. I've looked several times to see exactly what gets unlatched (and why the white clip doesn't seem to do much), but I really can't see exactly what's going on.

With regard to metal tabs on the water pump gasket, another option would be to cross-cut the metal gasket with a wire cutter/dikes in 2 or 3 locations, then twist the tabs back and forth like a paper clip until metal fatigue eventually takes care of the issue.

I am out of town right now, so do not have access to Rheingold. Thus I don't know the torque values for the egr valve and throttle/anti-shudder valve.

Interesting to see the carbon build up on the egr valve. It looks similar to what mine was like at 80,000 miles. Otherwise, congrats to you - looks like you've done the hard part!

Regards.

I'm hoping that p2457 fault code I'm having is just because of the carbon build up and the thermostat.

Frustrated that it was Sunday night no where to buy a cross cut chisel and desperate to remove the gasket. I ended up improvising my own cross cut chisel using screw drivers I got free from harbor freight and a random bench grinder I got from harbor freight as well years back because it was on sale plus coupon. Coz you'll never know you need one lol

http://i27.photobucket.com/albums/c1...psyddctr12.jpg

Pic of the egr. Valve after brushing and spraying with a $1.99 carburetor cleaner.
http://i27.photobucket.com/albums/c1...psqedmdma7.jpg

Sgrice, I've replaced EGR cooler thanks to your post and detailed description. And planning now to replace thermostat(s).
But I forgot to say, that I found out easy way to manage (disconnect/unlock) these connectors, that you have found tricky to disconnect. All you need to do is to squeeze it a bit and pull. Pics attached:

Shaman -thanks for that - great info! It seems squeezing the clip lifts it off the locking ramp and allows separation. Great tip!!!

Again, thank you so much to sgrice and all those who contributed on this thread. Took me 4 days due to work schedules but I was able to get it done. Temp is finally working well back to 89-90 degF during normal driving.

Some of the frustrations I encountered.

Initially positioning the new metal gasket on the engine block (as per instruction) just didn't work out for me. I find it almost impossible to keep that area dry from coolant to hold the gasket in place despite the use of sealant. Made me realize the reason they used those tabs to keep the screw holes aligned. Metal gasket I got wasn't completely flat, pressing one side on the waterpump makes the other end pop up. Another issue: the moment it sits correctly in place, it easily slides off upon cramming the water pump in that limited space. Made a mess with the gasket sealant as shown below from the numerous attempts and had to wipe and clean them off again before they complete dry up solid.
http://i27.photobucket.com/albums/c1...pspzf2bwsy.jpg

Also tried with the screws on (taped to prevent it from dropping) to keep the gasket in place to no avail due to limited space. Braille method was not working for me looking for those holes as I was afraid to bend the gasket if forced in.
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Had to take a breather.
Eventually, I went opposite the instructions and ended up having to rest the gasket on the water pump and let it dry in place pressed down against a flat surface before installing. This turned out perfect for me installing it easily.
http://i27.photobucket.com/albums/c1...pszqcqcqft.jpg

I can't recall if there's something attached on this hook like thingy on the hard pipe that run into the thermostat.
http://i27.photobucket.com/albums/c1...psf41r4odc.jpg

diegoX - Great job! Way to stick with it despite some frustrations!

Just for completeness (and for anyone who sees this thread in the future), the torque for the 3 M8x27 throttle valve screws is 19 Nm. I could not find a value for the four screws that connect the EGR valve to intake manifold. I suspect they are also M8x27 thread and have the same torque value, but do not know for certain.

Also, the heater element hose you asked about in post # 150 is part # 5 in this Realoem link. It can be purchased from ECS tuning for $75 (the link is here). A lot of money if all you need is a clip, but as someone else pointed out, the hose can deteriorate and be a source of potential vacuum leak.

I did not have any of the problems you had with the water pump gasket. Cannot remember my precise technique, but I think I just used one of the bolts to keep the gasket in position. Everything fell into place without a struggle - just lucky I guess. Your technique seems to be a good one - I'll put it into the memory bank in case I come across a similar situation in the future.

Last but not least, the hook like part of the hard coolant pipe has nothing attached to it on my car either.

Again, congrats on the perseverance. Hope the code p2457 is gone and stays away!

Just for grins and giggles I checked with the local BMW dealer and asked for a quote to replace just the thermostat...

$810.64
4.4 hours labor

Ouch!
I didn't realize gold plating was optional.

Water pump gasket
 

diegoX and sgrice, do I need order water pump gasket separately or it goes with water pump?
I assume you did complete coolant flush, how much coolant do I need to order?
and off-topic question: where are you usually shopping for parts?
thanks!!!

Shaman -

1) The water pump gasket is a separate item - it is part #2 in this Realoem link.

2) I must admit that I took a short cut approach to the coolant flush - I did two "partial" coolant flushes (I define a partial flush as disconnecting various hoses such that the radiator/water pump/hoses drained, but not the engine block) rather than a "complete" coolant flush. Just seemed easier to me to do 2 partial flushes a week apart than try to find the engine block drain. Not as good as draining the engine block, but that's what I did. Doing it my way took just about one gallon of antifreeze and one gallon of distilled water each time.

3) Just to state the obvious, the water pump is separate from the original thermostat repair (though I would not disagree with replacing the water pump at roughly 100,000 miles as preventative maintenance if you need to do the thermostat anyway).

Hope that helps.

Stephen

Given all these faulty thermostat readings, I decided to check mine and of course it was faulty. I had planned on changing this when my work schedule got a bit quieter. Interestingly, I called BMW Seattle today to book my X5 in to get the faulty DeNox reading fixed (hopefully under CA emissions) and to my surprise the lady on the phone said my vehicle had an open recall on a faulty thermostat. Mine is a 2012 X5d. Maybe some of you have the same open recall. I was very relieved to say the least.

Thank you, Stephen!
Regarding changing water pump - I had recently broken bolt under one of the pulley, so serpentine belt came off and I had a chance to check water pump for any damage and backlash. And it has very little one. So I think once I will be there - I will replace it.

Igor

Shaman, I got my parts from the dealership (BMW Roxbury NJ). They were the only dealership in my area giving 25% off on parts. Other AEM parts I get from rockauto.com

I think I was one of the first people around here to replace thermostat in my X5 35d.

I don't have the record with me, but it was about 2 years and some 30K to 40K miles ago.

I've noticed most recently that the temperature is starting to get twitchy again: when I commute to work I do notice that there's a certain downhill section along the freeway where the temepreture gets in the low 80s.

The thermostat is slowly degrading just like the old one and I suspect that coming winter time I'll replace it again.

Given that the ones available new appear to be just as bad as the one that was originally fitted (i.e. doesn't seem like nothing has changed) I'll probably not buy an OEM anymore.

I'm not entirely sure who makes it, but looking at pictures it doesn't seem to be Mahle, Febi/Bilstein or Gates.

Notice how in these 2 the center disk is attached differently.

Here's the BMW OEM from down below:

http://www.xoutpost.com/attachments/...ics-t-stat.jpg

Here's the Gates:

http://www.pl-parts.eu/environment/c...a88420f929.jpg

I'll give Gates a try on my next one see if it's any better. The cross reference part number is TH35488G1

Sounds like the woes we E39 M5 owners experience. No idea the failure mode except the thermostat seems to rub on the seal and over time the spring can't overcome the drag. Could be the seal doesn't sit right or the thermostat sits crooked. Who knows what the problem is with the X5's thermostat.

Knock on wood, my thermostat at 90k+ miles seems to be functioning well. 84C+ even in cold weather. The only time it's lower is sometimes when it's really cold but I never see it below 80C unless I'm coasting down a long hill and it's cold out. Sometimes it takes a while when it's really cold.

I'm going to start paying closer attention.

I've calculated over 32 mpg in the right conditions, maybe 28 mpg in the real deep winter highway driving.

Finally was able to change my thermostat today.

It took me exactly 4.5 hours from start to finish. Not that hard with help of this thread! Great job OP!!!

About that white connector you mentioned (that connects EGR cooler to some other connector) - you pull white thing back and firmly push it down, I used pliers but was able to repeat by hands as well. Tricky connector I must say. You need to do it in two steps.

All other very close to what was described but I did not take off air hose coming from the intercooler to the throttle/EGR valve (big one on driver side with metal springs), I just undid top part and move it to the left so it clear way to take off shroud. Also, I did not take off intake muffler, it looks like you did that to fight with that stubborn connector. I did not find why else you need to take that off.

All the rest as in DIY.

I think mine stuck shut for a while.Hit 204*F when I shut it off. I noticed exhaust was really hot.So I hopped back in to see gauge .Ive never seen it past 188-190*F ,usually 184 tops.Went for a ride and shot back up to 197*F then cooled to about 190*F for a few miles.Still higher than usual.I bought a ScanGuard after reading this thread to keep my eye on temps.I don't think it has EGT.Do you think it's the thermostat?

Do you mean ScanGauge? It has limited use with the X5d but I'm working with the company to get more commands working like EGT, transmission temperature, oil temperature, etc. and fully compatible firmware. Water temperature works great.

You didn't say what the outside temperature was or what you were doing but I've seen 210F before for brief periods on the hottest days and after hitting traffic or having stopped after a cruising period. Driving around,180-195F is pretty standard for me whether it's winter or summer.

Yes scangauge.It was only 80* out with a steady 45mph of the last 5 miles before shutting car off.I restarted car to see the 204* after noticing the hot exhaust tings.It was 15* cooler out and car temp 20* higher than normal.Funny thing is I've tried to get car hot,191* tops and only for a brief second.Thanks for your reply j52

The dealer recommend not using my Scangauge.Said a lot of codes tripped at one time.Lots of random codes that's didn't go together.Must have been when car cut out for split second and dash lit up on highway.Said I'd buy a new thermostat because they didn't change it because of no code?He said it isn't just a swap it had to be reprogrammed when swapped?

Wow!!! They said that new thermostat needs to be programmed?? Run away from that dealer if they told you so...

Throw in a bit more words... I know you know what you meant, but maybe explain what this means??

He might have ment the dash needed cleared if it got hot and I just change thermostat on the road.But I'm sure he said it'd ( thermostat) needed programmed.
The car is still under warenty,they don't change thermostat without a code or them seeing car HOT.I told him I'd get a new thermostat in case it needed changed out on the road.He said it wouldn't do any good because they'd have to program it.Said it'd be in limp mode but I think he took those words back and said the dash light would have to be cleared.From what I've read ,when thermostat shows signs of messing up it's not long after it takes shit.

Thank you sgrice! Mine has 170k miles and discovered the thermostat was stuck open, plus had a code for the EGR Cooler Performance. I followed your instructions, without which I could not have done these procedures. I discovered that the door of the EGR cooler was stuck, and the inside all charred up. So I wound up replacing that as well. It passed NYS inspection and running fine ever since.

Here is what I did differently from you:
1) I left in place duct #3 before the MAF sensor, no need for Tite Reach tool.
2) I removed the plastic cover below the fan shroud, and the steel cross member underneath it. Originally I was trying to find the coolant drain cock, but ended up cleaning a lot of leaves and dirt out, and eased shroud installation.
3) I drained and collected about 2 gallons of coolant by disconnecting the long thin (about 35 mm) hose below the radiator shroud bottom cover. Minimal mess, and virtually no additional coolant leaking when later disconnecting any other hoses. Refilled the cooling system at the end with a vacuum filler.

Thank you again for the detailed work procedure that allowed me to brave this job!

2010 xDrive35d

Andras - thanks for the comments. I have edited post #1 and added your comments about the tight reach tool not being absolutely necessary. In particular, I have since found that if the radiator fan/shroud is removed first, then there is adequate access to the air duct clamp bolts. Though I still think the tight reach ratchet is a handy tool to have on hand, you are correct that it's not totally necessary. I also added a reference about which radiator line to disconnect to minimize spilling/mess.

Appreciate the feedback - comments like these make it easier for the next person.

When you say "the door of the EGR cooler was stuck," do you mean the EGR valve, rather than the EGR cooler? I assume a replacement EGR valve would be a lot less expensive than replacing the entire EGR cooler. Regardless, glad you got it straightened out!

Regards.

The EGR cooler has a door in the middle, which was stuck partly open. The vacuum box could not pull it open and the spring could not close it. After disconnecting the vacuum box, I was unable to move it manually, not even with pliers. I replaced with new parts both the EGR cooler and the temperature sensor on it. That is the one with the short wires and the connector that you had so much trouble disconnecting. The EGR cooler comes with the vacuum box, mounting bracket, and one mounting bolt. The other mounting bolts are reusable per BMW. I'm glad I was able to contribute to your write-up in a small way.

Changed thermostat as part of long list of things done over past 2 weeks while on vacation.
Now seeing the temperature showing toasty 90-95C in town, up from 70-75.

What gasket sealant should you use on the water pump and / or Tsat?

I did not use any gasket sealant on either. The thermostat has a rubber gasket, and the water pump a metal gasket - those seemed to do the job for me. I've seen a number of people debating the pros and cons of additional gasket sealant. So some people recommend it, but I did not use any. The new thermostat comes with its rubber gasket in place. If you want to replace the metal water pump gasket (which I did), you need to order a gasket separately - it is not included with the water pump. You can check post #146 (and a few of the subsequent posts) for a discussion of torque values, and a method for removing the old water pump gasket.

I ordered the following parts for my 2010 BMW x35d
143,000 miles

I ordered the following BMW parts

11517801063 BMW water pump
And
11517793796 BMW water pump gasket
And
11517805811 BMW thermostat with gasket and o-rings

Fcpeuro (water pump and gasket) and ECS for the thermostat had the best price shipped to my door!

Almost certain I ordered the correct partS

I'll have to look at the water pump gasket again as it doesn't look like metal

The information below is from RealOEM. The link is here.


No.
Description Supp. Qty From Up To Part Number Price
Notes 01 Remanufactured coolant pump, mechanical
1

11517805812 $192.79
ENDED 01 Coolant pump, mechanical
1

11517801063


02 Gasket Steel
1

11517793796 $13.58

03 Torx screw with collar M7X42 4

11147792545 $0.72

04 thermostat with adapter
1

11517805811 $52.64

05 PROFILE-GASKET
1

11517787692 $6.02

06 O-ring
1

11517788984 $1.19

07 backup ring
1

11517788985 $1.61

08 Hex bolt M6X20-ZNS3 4
01/2013 07119904169 $1.25
ENDED 08 Hexagon screw with flange M6X20 4

07119905546 $6.73

09 Connector
1

11127806196 $10.41

10 PROFILE-GASKET
1

11122247745 $5.44

11 Hex bolt with washer M6X25-ZNNIV SI 3

07119905400 $0.65

Notes

• ENDED = the part has been discontinued (no longer available).

So you have the proper part numbers. As shown above, part #2 is "Gasket Steel" - and I remember mine as being metal, but with a black coating on it - as shown in the pictures of diegoX's posts 156 to 161.

I suspect you have the proper gasket - maybe the black coating made you think it had a plastic component?

Anyway, good luck with the job!

I got my water pump and thermostat changed for $450 by Indy. I supplied BMW on parts.
Coolant temps 88-93 celcius
Mpg up from 21.5 to 23
Regenerations occurring more frequently and all is well per Carly
Great thread!
145,000 miles and counting

Price sounds about right. I paid similar but had my Indy source a new thermostat as part of it, and he charged me a bit for battery registration. Think all in price was $550 (parts, coolant, labor, etc.)

EGR COOLER QUESTION
 

Hi guys! Maybe off topic but does anyone know if the OEM EGR Cooler I will about to purchase from the dealer has been improved by BMW? I think mine just gave out and getting inputs if there's a better after market or just stick to the OEM which doesn't last. Thanks

What do you base your opinion about yours being bad?

Forgot the exact code but it has something to do with egr cooling system. At 90K miles I think it's time for replacement considering its a common problem. Thanks

Finally took care of the T-Stat, Water Pump, Idler Pulley, and Fuel Filter today - took about 6 hours in total (My ABC's are missing). Thanks for the great directions - makes senses what you start poking around. I'm a C- mechanic but learning my way.

Only issue was that I replaced a seal on the lower red boost hose - it didn't seem to seat properly when I was under there and sure enough it wasn't set right when I drove off....

I can't quite figure out how to seat it properly - anyone dealt with this?

https://dl.dropboxusercontent.com/u/..._121821134.jpg

https://dl.dropboxusercontent.com/u/..._124146803.jpg

Was able to get the boost pipe back on the following day - push up with right hand while pulling down with left hand. You will hear it click in.... total pain in the arse...

Temp is running solid 88-91 now - back in action.

I haven't had time to do this on mine (73k miles). I tried a kludge for a 200 mile trip I took on Saturday where the ambient temps were around 15-20 degrees. I put thin cardboard over the radiator, leaving the center mounted ATF cooler exposed (and about 3" of the main radiator exposed). Even with this much blocked off temps never went over 74, which is 2-3 degrees above the without-cardboard situation. The efficiency of the cooling system is pretty impressive, eh? Anyway I remove the blockage and I just need to find a free Saturday to do the real fix. Just need some decent weather.

I have my parts on order to do mine. Coolant temps dipping as low as 65°C while driving in mild weather on the interstate.


Does someone have the torque spec for the aluminum water pump bolts????

After change
My mpg up from 21.5 to 24.2!
This will pay for itself

Where did you get your torque values for the water pump bolts? I don't see them in the OP and I don't have a working gt1 at the moment.

Mine (preliminary) went from 18.6 to 25!!

Mine would not rise above 68c
Few distinctions that might be of interest:

1. Instead of the OEM I bought Beck/Arnley 143-0904 Thermostat Housing. from ebay member 3wardist for $44.67. housing is identical except for the serials and bmw logo. the internals are not the same. you can see oem on the left here and the Arnley on the right.
mainly the Arnley has a bigger copper core, and the springs have a lot less travel than OEM. Which one is a better part not sure but I will be happy to post when it fails.


http://i.imgur.com/JVvyizMl.jpg

2. 2 of my t-45 torx nuts on the egr cooler had already been replaced by regular nuts presumably by the dealer. After dropping the non magnetic flange bolts 3 times and finally losing one of them I went to home depot and bought the identical length/thread bolts. this is the size in case someone is wondering.
http://i.imgur.com/vWmXZD7m.jpg

3.I noticed the EGR valve which had been replaced 18k miles ago by dealer with the updated part was completely caked up in soot. So was the throttle valve and so was the intake manifold.

http://i.imgur.com/cbmrQ4ol.jpg
http://i.imgur.com/q0NNB5tl.jpg

This is what came of the EGR valve alone
http://i.imgur.com/SSc2Bkrl.jpg

Id be interested to see others egr valves to see if this is normal caking up procedure for diesel engines or if this was caused by the failed thermostat or if this is just what egr cooler does to our egines the car has 103k miles.

Either way it seems a glow plug/injector/EGRvalve/catalitic converter/dpf filter/engine would not last long if this contamination was being constantly pumped in.