oil separator symptoms
 

what are the clues or symptoms when it's about time to replace the oil separators?

oil separator
 

guys, i'm about to change my oil separator for a preventive purpose.

pls, tell me what i need to purchase from the attached diagram of the oil separator. cheers

anybody

All of them while you at it and dont foget the valve cover gasket too.

Here is what you need exactly for a 3.0I, the realOEM diagram is not totally correct. I got the usual OS (not the insulated one) as I'm living in hot climate.
As said above, you need the valve cover gasket too and also the throttle body gasket. I'd add too the dipstick tube o-rings (one large at the bottom, two small at the top)

What are the symptoms?

what's the part number for valve cover gasket and throttle cover gasket

Valve cover gasket: #16 on this diagram: RealOEM.com BMW E53 X5 3.0i Cylinder head cover

Can't find the throttle housing gasket in realOEM, here it is in the Pelican parts site: Pelican Parts - Product Information: 13-54-7-504-729-M17

Dipstick tube o-ring: #11 and 12 here: RealOEM.com BMW E53 X5 3.0i OIL PAN/OIL LEVEL INDICATOR

Search in this forum and you will find tons of information about OS. Most common symptoms are rough idle, major oil leak around the OS itself or to the valve cover gasket, codes for misfires and O2 sensors. Most of the OS separator problems occur in very cold climate but can occur too in hot climate with less annoying consequence though.

Would the separator throw out a code? Or would the mechanic need to manually inspect the vehicle?

Mine threw out codes for misfires on all cylinders, O2 sensor limits, O2 adaptation limits. I got a small oil leak to the valve cover gasket too and another (bigger) to one of the hoses coming to the OS, however once again I'm driving in hot climate so I didn't experienced some major issues described by some owners living in very cold areas.
Depending of your mileage and how old your X is, replacing the OS is one of the most useful preventive maintenance...

thanks for the help.

thanks for your input sfcl!

from the picture i upoaded, do i also need to get #1 too or just hoses?

BMW makes a $450 kit that wraps these pipes, it plugs into the wiring harness and keeps the oil separator warm. My car has a bad separator too, I could here oil squirting from behind the engine onto the block.

from the picture i upoaded, do i also need to get #1 too or just hoses?

#1 is the OS, you need to replace it AND the hoses, common cause of oil and air leaks. To be complete on the subject of air leaks on these motors, I wouldn't replace the OS and its hoses without replacing also the intake boot and the various vaccum lines. They are not expensive and you can take advantage of the OS replacement job to be sure that everything is ok while you are at it...

I had my dealer replace the OS, hoses and dipstick tube last January when it all froze up and blew out the valve cover gasket. Would it be unusual to have a problem again this year even though I've gotten new parts installed? Last weekend she had some rough idle early in the morning after the vehicle sat out overnight. I checked the dipstick and under the oil cap and there was a small amount of the teltale milky oil. I'm wondering if I need to replace the OS again or can I just take it apart and clean it out? Would cleaning it out just delay the inevitable?

Yes, cleaning it out is the appropriate action if you have replaced it a year ago. The buildup of condensate is only inevitable if you don't drive it long enough to get it hot, at least hot enough to boil off the condensation.

i was just told by a professional that the oil separator for e53(os and its hoses) is same as e46. pls, advise.

there is also a "cold climate version". from northeast. is this necessary?

sfcl, also RealOEM.com BMW E53 X5 3.0i Hot-film air mass meter

see if this is what you were referring to for intake boot and various vacuum lines. pls, indicate with numbers as you did before. cheers!

Yes you can absolutely experience the very same symptoms as soon as well...yes the very next winter..

People the oil seperator is an ongoing thing..Meaning just because you get the parts replaced (including the VCG) it doesn't mean anything.. Its not like other parts on the car like a water pump or something. This part will go through continous abuse if you do not clean the hoses and check the cap regularly especially if it sits overnight in cold weather and sub freezing temps. This part is always prone to fail if neglected in such terms, in conjunction with short trips..

The best thing you can do is limit your short trips. The condensate builds up and freezes up because the car has not been driven long enough (needs to be longer then 30 minutes) to burn off that condensate. As a result it freezes, that milky crap under the oil cap is a sign of this happening. Of course, I've seen super milky, paste, and barely any milky crap at all..It can vary.

The newer insulated oil seperator parts are helpful, but not a total solution. The insulated hoses and wraps keeps the condensate warmer longer, but does not prevent it from freezing up also..Especially if left sitting overnite in sub freezing temps like I said..

Do a search on this topic folks..We cover every possible scenario with the Oil seperator on this site. There must be at least a 100 seperate threads on it. GL.

I'm sure JCL will chime in soon with greater detail then i can provide..

On 4.4i - does one need to change the valve cover gaskets as well if replacing the oil seperator lines? I see this in my near future.

I am in the process of doing this right now. I have everything off but the OS stuck on one vent line back up to intake maqnifold.

I called a good reputable BMW dealer today (actualy called three) but the one that was recommended said that the new "fix" which folks here have talked about for years is an insulated OS valve plus new complete dipstick and the three hoses (1 going from valve cover to Oil seperator which connects to OS on bottom side, one hose going from top of OS to Intake manifold and another tueb, and the htird goes to the bottom of the dipstick.

I am taking pictures and will in the next week up load the process for my 2003 X5 3.0I.

By the way if you haven't done it and you live in the northern part of the country where it gets down or below 20f, I would do it, no questions asked. This is a poor design. Mine just failed and I was lucky and the motor died with too much oil on the plugs / in the cylinder. I had couple of ounces in each (guess), but if I had known how serious this problem can be (total the engine if it fails one way) I would have done it.

Same problem on all engines? What if you let your engine warm up? Should I be considered if a take some weekend trips to Tahoe and I'm not garaging? Most of the time i'm in SF, and even it Tahoe temps usually don't get too much below 30F.

I guess If I were to change it out I would use the insulated one if it's supposedly better.

sfcl, also RealOEM.com BMW E53 X5 3.0i Hot-film air mass meter

see if this is what you were referring to for intake boot and various vacuum lines. pls, indicate with numbers as you did before. cheers!

i was just told by a professional that the oil separator for e53(os and its hoses) is same as e46. pls, advise.

Intake boot is #8 on this picture. Vaccum lines, there are several... One coming from the part #10 on the picture but there is also another coming close to it, on the same elbow, not shown on the picture. The best way is probably to get 2 or 3 meters of brand new vaccum lines (I guess this is about 3.2mm internal diameter, sorry I don't know in inches!) and replace all what you find!

i was just told by a professional that the oil separator for e53(os and its hoses) is same as e46. pls, advise.

It may help those new to this issue to know the failure mode for the oil separator. The oil separator failing doesn't cause the problem. Primetime outlined this above, but here is a bit more detail.

All engines get condensation inside them, worse in cooler weather. When you get the engine good and hot (30+ minutes, preferably more), the condensation burns off. If you only do lots of short trips, it never burns off, and it builds up. It forms a milky paste that is visible under the oil filler cap. If you don't have this build up of condensation, the oil separator is not going to be an issue until the rubber hoses go soft, usually in 5 years or so (similar to rad hoses).

If you drive for long enough with the condensate building up, it collects in the oil separator. Still no problem.

Now, if you have that buildup, and it gets very cold, the condensate can freeze in the separator (since it has water in it). That is what is being referred to as the separator failing. It isn't really failing, it is just freezing. It isn't even freezing itself, the gunk inside it is freezing.

The insulated separator has a higher tolerance for low temperatures before it freezes, but it doesn't solve the problem (the condensate), it just tolerates colder temperatures. Personally, I have never had a separator freeze (even in -30C), but then I don't tolerate lots of short trips as that is very hard on the vehicle.

Even if you have the new and improved separator, it is worth checking the separator every few years (not sure what interval is right for each individual) to see if condensate is building up there. If so, clean it out. That is the best preventative measure, even better than putting the new design parts on. Eventually the separator will fail (rubber goes soft) and then it is a toss up if the new and improved one is worth doing or not. Can't hurt.

Hope this helps those who are trying to figure out what to do after an OSV freeze up.

Hi JCL, you are all right of course however some people could have a tendency to think that it is just necessary to clean the OS, not to replace it. Although this is often true, in my own case I wouldn't have been able to clean it, too much hard deposit inside, I'll try to post pictures of the open old OS when I can. New OS is cheap (50 to 60 dollars usually) and most probably one of the hoses or their o-rings will fail during the removing process, so I guess that the best way would be to replace it with its hoses, worth it when you spend not less than 3 or 4 hours to do the job (at least for me!).

I believe there is a seal kit available for the separator (at least some models of it). I agree that when it is opened up, if it needs seals then it is a choice of resealing it or replacing it. My intended comment was that if you have new parts on it, it isn't necessary to replace it every year, but rather to clean it out. It does have a finite life, however, and at any piont replacing it may just be easier.

i was just told by a professional that the oil separator for e53(os and its hoses) is same as e46. pls, advise.

How would we know? You gave the link to REALOEM above. Simply look up both models. Same part number means it the same item. Not sure why it matters, unless you have a stock of E46 separators to use up. This issue is in no way specific to the X5, but is common to many BMW models.

Call up your dealer and ask them..problem solved..

About OS, I forgot to mention something interesting: I had at home a whole OS and hoses set, Contitech brand for the hoses, Febi por the OS, that I purchased some months ago. Once I decided to replace the whole system, I wondered if it wouldn't be better to get genuine BMW parts (means supposed better quality) as this is not the job that I'd like to do every month!
So I ordered a set of brand new BMW OS and hoses and tried to do the job. It took a little more than one hour to get the old OS out, no problem except that I had to cut the old hoses (brittled) to get them out. And it took about 2 hours to only try to put the small "S" hose coming from the OS to the valve cover (the one which needs to be rotated)!! No way to click the hose on the OS, even with some silicone lubricant. It was already hard to fit with the OS outside of the vehicle and simply impossible to fit on the car... After 2 unsuccessful hours, I got the Contitech parts and immediately noticed that the design was far more better! Put them on the vehicle and after one or two tries, the hose came to the right place with no real effort...
I got a look after that to the BMW parts when I had more time. To get the hose on the OS easily, I finally needed to use a file to slightly reduce the int. diameter of the clip ring...
I don't know if it was a bad batch of parts ot whatever but it could be helpful for those who plan to replace the OS and get the same problem.

This is an excellent explanation and very informative. Thank You.

You are very welcome.

I've read quite a few posts about the oil separator problem, but I've not seen any information about whether or not this can occur on a diesel.

Just yesterday I bought a 2010 X5 xDrive35D, and it will be delivered next month. We live in Utah, and have a heated garage, but it sometimes gets pretty cold here. Rarely below 10 F, but sometimes below 0 F. Our shortest drive would be 15 minutes or so one way, down, then up the mountain.

So, is the diesel engine subject to the OS problem? Will the sort of driving we do ... perhaps to go out for dinner on a cold night ... be a problem?

Thanks ... and wish me luck with my new car!

While a diesel requires a crankcase ventilation system the same as a petrol engine does, I have no idea if the new BMW diesels are using anything similar in design to the traditional oil separator valve that is discussed above. It doesn't show up in the Realoem parts catalogue, but that may be due to changes in the catalogue as much as changes in design.

I wouldn't spend much time worrying about it, enjoy your new car. If you do a lot of short trips, you may see some accumulated paste under the oil filler cap, and if so that indicates that the engine isn't getting hot enough to burn off the condensation. That is a better thing to check in my opinion than trying to chase down a problem that may not even exist.

Thanks! Sounds like good advice!

Temperature Threshold for Improved Oil Separator/Tubing Heaters?
 

I live in fairly cold country (Northern NV) and am planning to purchase a used 2002 or 2003 X5 with the 4.4 V8 engine. Since this car may spend a number of nights outside in the winter cold, is there a certain low temperature at which I should retrofit the engine with the insulated Oil Separator and the electric heat blanket? It's sort of a pricey and Rube Goldberg retrofit, so I don't want to do it unless the mod kit is really needed.

For example, are the improved parts needed with night time lows of 20F? What about 5F or 10F or 15F? We regularly see winter night time lows in the teens around here. I had an experienced mechanic around here tell me that he didn't think the improved parts were needed, but the last time I checked, a car sitting outside and not operated for several days will get pretty cold, especially if daytime temps stay below freezing. So I am leery of blindly following his advice. What is the experience and recommendations of the forum members on this subject (for the nighttime temps I have noted above)? Thanks.

The real questions are (1) has the oil separator ever been serviced on this used vehicle? and (2) are you planning to do lots of short trips that don't allow the engine to warm up fully? The separator isn't the issue, and the cold ambients are only a contributor, not the cause. See post #32 in this thread for more details. It isn't a case of a temperature threshold as much as it is a case of allowing the engine to warm up completely and burn the condensation off. If you do that, there won't be much in the separator to ever freeze up, no matter what the temperature is.

In terms of cold start capability, I didn't have problems with my 3.0 parked outside occasionally in -20C to -30C. No external heat source. As soon as I had a stable idle speed I would drive it (gently) so that it warmed up as quickly as possible. Nothing worse than leaving it idling with no load.

JCL,

Thanks for your informative response. One of the reasons that I am concerned about the 4.4 engine in my environment is that I will be doing a likely mix of 3-5 short trips (2-5 miles in length) for every 60 mile trip that I take. Because of the heavy expense that can occur if the crankcase ventilation system freezes up, I will definitely be taking the beast apart and cleaning it up and replacing hoses/parts as soon as I purchase the new-to-me vehicle. I guess it might be advisable to do this inspection/cleaning twice a season in the winter.

My V8 Jeep is not nearly as sophisticated as the BMW in a number of ways, but at least I don't have to worry a bit about its crankcase ventilation packing up and taking the engine with it... I think I am still going to get the X5, though.

I've done quite a bit of research on this site concerning failure modes and the consequences of a frozen oil/water separator. It does seem to be a pretty serious problem that BMW could have done a better job in solving. Where was their long term cold weather testing program prior to entering production? Are there any home-engineered solutions that will keep these ventilation lines freeze-free in short mileage driving scenarios?

My OSV failed winter kit didnt avoid it
 

Left my '01 4.4 outside my warm garage (mistake) so we could have a new years party. started it up at -5 F and drove it about 5 miles realized I was one of those idiots leaving a giant smoke screen behind me. I usually laugh at those people cuz they dont know something is wrong.
my X has 113K on it, bought with 100K. After I had my wife pull me home with my trusty steed Yukon I pulled the oil seperator out, blew it out and there appears to be all new hoses, new osv and has an electric warming blanket around the hoses. It appears that the extra winter kit doesnt help all that much. I took the throttle body off and stuck some rags down in the intake and got a lot of milky oil out of there.
after running it for half hour it appears cleared up, must have been lots of oil in the exhaust. I ran it for 5 minutes the first time and took throttle body off to check for more oil, which there was a little, but not much. Decided to run it longer the second time and checked again. Looked good after that check.
I dont get it, do I have to drive something else when it gets really cold out. My wife had parked it after a one hour drive, shouldnt have been a big problem with condensation.
I thought some of you might be interested to know that the extra money spent on the cold weather parts dont really seem to completely fix the problem, although they may help, who knows.
The X normally gets drive 25 minutes to and from work on a very regular basis. If it wasnt so awesome in snow, which we have a lot of, I would get rid of it. I called the local dealer and spoke with a tech who was very helpful, he said if all those parts look new to just blow it out and reuse it.
In the 6 months I have had it I was stranded by an alternator (trans fail safe warned me a couple times), tailight problems, display issues on radio, now the OSV. Its going to be a long winter.
Thanks to this site I am able to figure these issues out. Fantastic information on here and I dont know what I would do without it.

Wilk:

Good diagnosis, and exactly the right course of action, IMO. You are right that the new parts don't fix the problem, they just raise the threshold somewhat. Unless you know the history before you bought it, the condensation could have been building for a while. Check it every year, clean it out if necessary, and you should be fine.

Glad the site is helpful.

Wilk,

Thanks for sharing your not so wonderful experience with the Oil Separator Modification Kit. Driving for an hour should certainly help to get the water out of the oil, unless your thermostat is not working correctly and the engine is running too cold in the winter.

It's beginning to sound like X5 owners in cold climates need to pull their engine oil caps and look for moisture buildup inside the caps with just about every gas fill up during the winter months. Hopefully someone has developed or will develop a better fix than the factory's marginal approach to this condensation problem.

Are you serious?

You take annoying to a whole new level...I'm sorry.

For my 2003 X5 3.0 it did not throw out a code, which i thouhgt was wierd. Mine just happened two weeks ago.

I'm new here and really learned a lot reading all these posts. So, thank you :)
I believe I have this oil separator problem. I live in Kansas City and it's been sooooo cold here. I started my car the other day, I have an X5 4.4. I let it warm up for about 15 minutes. The temp outside was about 5. I put the car in reverse to back out and it's kind of sputtering....I pull forward and notice a huge amout of smoke coming from the exhaust. I freaked out, though it was on fire! I get out, look...the check engine light is flickering off and on. I immediately park the car and turn it off. Run in to call my husband who is in DC working. He doesn't answer. I go back outside and take a look and there is a HUGE oil spill underneath. I haven't taken it anywhere yet...waiting for my husband to tell me what to do. I know I can't drive it. I should say my drive to work is less than 5 minutes, that's why I always warm it up before leaving. So, from what I have read here, I believe I have the oil separator problem. Does anyone know how much this costs to repair? Seems like any repair is at least 2,000! I've had my share of problems with this car...I was hoping to get a break for a while. It's a 2002 with 115,000 miles.

Here is a short list of things wrong with it right now.
Rear left passenger window just fell down. I have it duct taped up....real classy, huh?
Windshield wipers just stopped working. The right one doesn't move at all....the left ones moves about 3/4 of the way.
The key remote has never worked...about 1 week into owning the car the door lock fell in. Now there is a hole where the lock should be. We took it back to the dealer and they had to "order" the part. Well...my husband was deployed and we just got back to KC in October....so the lock was never fixed...oh and it took 4 months for them to get the part in!
We also had a fuel sender problem...they were replaced about a year ago....cost 1200.00. I can't remember the exact thing that happened a month after the fuel senders....but that was over 2000.00!!!

I LOVE this vehicle...but it doesn't love me and I wish I could sell it :(

Any help is much appreciated.

PS...Someone said on here to just garage the car for the winter....no can do, this is the only car I have. I bought this car because I thought BMW's were such great cars. Never in a million years did I think it couldn't handle cold weather. I don't know anything about cars. My husband can fix just about anything...this car has him beyond baffled! I should have mentioned in my post above that we have an excellent independent guy that works on it. He's like 100 miles away and I can't get it there for a couple of weeks!

pls, provide the part numbers for vaccum lines and others you mentioned above. thanks

guys,

went to my mechanic with an oil separator kit for replacement and was sent home by my mechanic who said the kit doesn't need to be replaced ever. what's he talking about?

I think he's telling you that you should find a new mechanic. ;)

The oil leak is just the oil running out after the failure of a gasket or separator line. Don't drive it without oil. After you get the oil separator fixed (could be up to $1000-1200, depending on what it needs), you should modify your driving habits. The oil separator fails because of condensate building up in the oil, forming a paste, and clogging up the separator. The condensate forms because the engine isn't being warmed up sufficiently to burn off the condensation. You should not idle your vehicle to warm it up, that is making it worse. When you start your vehicle, wait until the idle speed stabilizes, ie about ten seconds. Then drive it, gently. It is better to drive it than to let it run for an extended time cold. What you want to do is minimize the duration of the warm-up cycle, and that is best achieved by putting moderate load on the engine, ie driving it. Your manual covers this, and it isn't specific to BMWs.

If you have a lot of short trips, you should ensure that you get a longer drive in every now and then, to get the engine good and hot and burn off the condensation. Given the number of short trips you make, which is brutal on a vehicle, you should also change the oil more frequently than the service lights indicate, as you would qualify for a severe service interval (double the frequency).

Hope this helps. Good luck.

Thank you, thank you, thank you....you explained that so well. I really appreciate it :)

Update
 

Three days ago I had the giant white cloud following me, burning oil, OSV failure. I cleaned the OSV and after assembling it seems to be ok, but still blowing some smoke for a couple days. Burning out the exhaust because I am sure its coated heavily.
Question, do I need to pull the hard lines that go down the back of the block and clean them out? Does the dipstick tube need to be cleaned out as I have seen mentioned. I have to believe that the hard line down the back of the block is the real problem, maybe having oily white buildup and freezing. The OSV is pretty big to freeze up, but the hard lines are quite small.
Then the drivers handle carrier broke. sitting in garage with one door unlocked, wife calls, cant get in my car. I almost used a hammer but I got in. The real issue was that her makeup was in the back seat.