Coolant system antics
 

03’ e53 3.0 had head gasket 13k miles ago. Recently getting low coolant warning, comes back 2-300 miles later (doesn’t get lots of mileage .) Top off, move on. Dash temp sensor rock solid straight up.

Wife said a tiny bit of white smoke on cold start. Little stumble on cold start also, goes away on second start.

Noticed upper and lower rad hoses were tight when warm, this morning the rad hoses were slightly less tight but good bit of pressure when I loosened the overflow cap.

Pretty hot where I am, mid 90’s during the day.

Anything I should worry about?


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You probably have a bit of head gasket/cracked head problem.

Are you sure both your fans are working? Aux fan (comes on with AC) and clutch fan (newspaper test)?

If you are losing coolant, you have a leak and have to find it.


To RULE OUT a head gasket problem, run the car to temp one day, and let it sit overnight with cooling system closed. The next morning, before startup, pull plugs and swab each cylinder looking for coolant. I found coolant in cylinder 6 in this manner.

These cars usually take head gaskets pretty well.. but why did you need a head gasket 13k miles ago?

Btw - 2 months ago, you mentioned a stumble on cold start-up…BUT no coolant loss…did you ever figure it out or is it the same issue?

I bought it several years ago with a leaking overflow tank. Thought I could replace the tank and go forward. Tank lasted about 2 hours. Block test revealed head gasket failure. Did the gasket in the driveway, worked fine 13k plus miles. Concerned it has failed again.

Started getting cylinder 5 /6 misfire codes CEL and fuel codes. Replaced coils and both upstream O2’s (bank 1 had a heater not working), and the CEL has stayed off for 40-50 miles.

I will check the viscous fan and the AC fan as suggested.

Thanks all.


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I’m going under it tomorrow to look for leaks, is it odd that the coolant hoses are tight after sitting overnight?


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Have a look at the spark plugs. They will likely tell the story or at least give a clue.

Brief followup, looks like the electric fan is not functioning- comes on with AC right?
And the cold start valve connecting hose was a bit cockeyed- maybe enough to create a stumble?


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The pressure tanks only last a couple of years. It might be going again. Put dye in it and look for the leak with a black light

If hoses are still tight (hard with pressure) after sitting overnight, that is a sign that exhaust gasses are entering the cooling system...

Yes Aux fan should come on with AC..It may also come one when you unplug the coolant temp sensor in lower radiator hose. It also flickers on at every start-up .

In my case both aux fan and clutch fan had failed, I didn't notice it (no error codes) and the car overheated in traffic while a family member was driving it.

Update: seems aux fan has failed. Put 12v to it, nothing. Ordered a fan. Need to test the switch also.

For the first time the fail fail popped up on my creator 310 Scanner but don’t see a module to test anything.


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The fan is has a built in driver and is pulse width modulated so not going to work by putting power to it.

Hmm. Ok. Is there a best way to troubleshoot?


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yes...

1. The fan should flicker on start-up
2. The fan should come on with AC..if AC is working
3. I am told if you unplug coolant temp sensor on lower Radiator hose it will come on when you turn the key ...I haven't tried it.

If the fan fails to turn on in above tests, replace it.

you can also activate it with INPA and other good quality 2-way scan tools.
and of course you can lay any known-good fan from an E46, E39, E83, E53 E36/7
on top of your engine, plug it in to your fan's connection and see if it works.

I like the TYC brand fan for E53 found on Amazon.

If you can't get it to run at all, make sure to check fuse F107 behind the glove box.



This is not the fuse that power the fan, according to newtis and the manual. It is the fuse that powers the fan in 2004 and later cars -- however, some 2003 cars appear to have switched over without proper documentation. There are two of us on this forum that have had fuse F107 blow and cause an inexplicable failure of the fan, only to find that fuse F107 was actually powering the fan.



Just throwing that out there if you can't get it to turn on at all when you turn the AC on. (Post #10 here: https://xoutpost.com/bmw-sav-forums/...continues.html)

Coolant system antics
 

Thanks.
Last PM I disconnected the lower coolant switch, no fan, shorted the coolant switch, still no fan.

Pulling Fuse F61 this AM before it gets to hot here.

One thing I’m curious about: the two vertical aluminum AC tubes next to the fan connectors get immediately scorching hot. Normal? Any cure for 2nd degree arm burns?

Lastly: mine is an 03’, how do you determine if it’s before or after facelift (I think it’s called ?)

I have a fan on the way. Looks like fun to get to it?


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you have a pre-facelift... '04 model year (sept '03 production) is when facelift started.

I have only replaced fan on a post-facelift E53 which was a couple hours involving loosening/removing the bumper, etc. I think I read the pre-facelift is easier, but not sure...Have a search.

Coolant system antics
 

Fuse F61- tests good. Waiting for the fan.

Thanks I thought I read in the Bentley that 9/03 was some sort of cutoff but I’ll defer to your knowledge.


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Not a huge fane of crawling on the ground I was able to change my fan out the top. I think I may have cut into some of the plastic ductwork to make It possible.

I do recall some of the bumper cover screws were rustes into the spring nuts and just spun the nut you can't access. I used a small hole saw to cut the plastic around the nut and used a larger head screw on reassembly.

I live in the rust belt your experience may be much less rusty.

This makes in obvious (and note that, as already stated, production of LCI began in Sept. '03): -

https://xoutpost.com/attachments/x5-...42471676_n.jpg

*edit* - NOTE!! LCI began in MY2004 (not '03 as indicated in above image)

Wpoll, in the US we did not get the LCI until model year 2004.

Yep - same for the rest of the world. The images above aren't mine (nicked them from another Xoutpost thread) - which is why I pointed out the LCI build date - the years on those images aren't quite correct and probably relate to production years rather than model years. :thumbup:

Sorry for the confusion... but actual date stuff aside, it's a great illustration of pre-LCI and LCI difference. ;)

Hmm, mine is an 03’ the profile looks like the top picture but mine doesn’t have the two sticking up doodads under each light.


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Coolant system antics
 

AUC sensor have any effect on aux fan?

So pre-LCI and it doesn't have headlight washers. :thumbup:

AUC module - it's an air quality analyser that is used to control the air recirculation when set to automatic.

Connected a replacement fan and after 3-4 seconds it starts up (AC on). Guess I’m gonna watch some bumper take off Youtubes.
Thanks for all the advice!


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Glad you fixed it! The X lives to drive another day

You still have an unexplained coolant leak…did you swab cylinders?

Yes, yes I do….
Disturbed that my low coolant dashboard light came on and it took a good bit of coolant….
No car stuff on my birthday though.


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Ok, pulled the spark plugs (NGK BKR6EGP looks like)
Tops look cooked, #6 seemed a little oily). Will be replacing plugs today-suggestions?

Probed the cylinders with a length of rope and no sign of coolant, tiny oil residue in #6.

I replaced 5 and 6 ign coils with cheap coils and #6 had actually slipped off the spark plug…..get what you pay for I guess.

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Wow, those spark plugs are cooked. Iridium spark plugs (BKR6EIX)
Coils: NGK U5055(24H20

7,000+ trouble free miles on mine.