Condensation under oil cap

[Bdc101]

This week I replaced my CCV with the OEM BMW cold weather replacement as prescribed by the service bulletin.

I had noticed some oil sludge and visible condensation under the oil cap which was why I knew I needed to do the CCV. I've had the car since Aug and most of my trips are short. Now that the weather has cooled off I knew the problem would get worse.

Anyways, I did the CCV and all the hoses, I cleaned all the sludge I could find, which was mostly in the CCV and hoses themselves but also in the air distribution manifold. Put it all back together and drove around for a day, parked in the garage and came back after several hours and found what appeared to be the same amount of pure water condensation, as well as some indication of sludge forming under the valve cover.

Am I missing something or was this supposed to fix that problem? Any help is appreciated since this is supposed to become my DD soon and I can't have it sludging up all winter, every winter.

Oil is less than two months old BTW, Mobil 1 5w-40 euro blend.

Thanks in advance!

[upallnight]

Nothing you can do about the condensation/sludge under the oil cap. It the nature of the PCV design that BMW went with. I believe on later BMW the CCV valve is integrated with the valve cover so that the heat from the engine is used to burn off the condensation or because the CCV is no longer sticking out in the cold air, there is less chance for condensation to form.

They probably didn't realize the consequences of condensation forming because they drink their beer warm.



Or you can do what I did, get another vehicle that doesn't use such a Rube Goldberg method of crankcase ventilation.

[e53fanaticc]

Upallnight has got it right. I'd also check to make sure the feed to the oil pan is fully over the lip of the dip stick pipe - sometimes this clogs up with the mustardy (is that a word?) slug, this causing the CCV not to perform as designed - a horrible design by the way.

[80stech]

There is no way the CCCV system can get rid of moisture (especially on a higher mileage engine) the way it is designed. The only solution is to "open" the crankcase to let even a small amount of unsaturated air in to carry the moisture through the system into the combustion chamber.

[NZBM]

bdc101, I had the same problem with my E46 coupe with 3.0 M54. We also have a E46 325i wagon with a 2.5 M54 (same CCV system) which has never had moisture/mayo issues, even though its driven similar trip distances/climate etc.

The way I finally cured the condensation sludge issue on the 330ci was installing the cold climate CCV and all four hoses, and fitting the revised cold climate dipstick tube. Also a new thermostat (if its soft failing it wont let the engine get up to temp quick enough)

All the above parts where contributing to the condensation sludge, but the main culprit was the original dip stick tube- the original oil drain passage is very narrow and gets blocked over time (the revised cold climate dipstick has a much wider oil drain back opening)

If you don't fit a revised dipstick tube, you at least need to remove and thoroughly clean out your original, refit with a new O-ring.

Cold climate CCV & 4 cold climate hoses, revised cold climate dipstick tube & new thermostat fully cured my mayo/moisture gunk issues.

[80stech]

If the system is "closed" and working properly there is no way it can get rid of the moisture (increased amount in higher mileage engine) because the combustion gases are saturated and the "water" seperator cyclone drains most of the the moisture back into the oil pan. Keeping the whole thing warmer might help but more like a band-aid than a cure.

[Bdc101]

Well I replaced all the hoses but did not replace the dipstick tube, but fortunately there was no sludge or buildup to be seen on the dipstick or dipstick tube. I did inspect and clean it and replaced the O ring.

It's a fact of how engines operate that crankcase ventilation systems can't remove all the moisture from the crankcase. Combustion gas is partially made up of water vapor as it is a product of combustion, so the gases entering the crankcase will always have moisture in them. Everybody has to deal with that. The problem is when it condenses and that seems to be the weakness of the BMW method of crankcase ventilation. I was hoping that the insulated components would prevent the moisture from condensing, so that is disappointing. My trips have brought the car up to operating temperature for 15-20 mins and yet there is still mayo forming. This is longer than my normal commute which is a bad sign.

I'll put the thermostat on my list if I decide to keep this car. It doesn't warm up any slower than any of my other cars, but I'll just add it to the list when doing a cooling system overhaul to fix all the things that were designed wrong there too.

[StephenVA]

The mayo accumulation on the underside of the cap happens on all vehicles that do not reach operational temps through short drive cycles. VW has the issue as well. Thoughts: The BMW six that sits in a closed space vs a large space (E46 engine bay vs E53 engine bay), will warm up faster, stay hotter longer, and will therefore have reduced condensation issues in cold temps.

Only preventative steps will help. Example: Change the oil (HOT) frequently during cold weather cycles. Take weekly LONG trip (2+ hrs) to see the sights during the winter months. Enjoy the season and your X5!

[Bdc101]

With all due respect, I don't think that's true. I've never once seen mayo before and have been wrenching for many years. I used to own several MR2s which are notorious for having long warm up times due to large coolant volume and common thermostat failures, and even when I had very short commutes and stuck-open thermostats I never saw mayo once in hundreds of thousands of miles. My 2009 Scion and skyactiv Mazda do not have this problem and have been subjected to over a year of the same commute as this BMW with no sign of mayo.

Also, this car only took one day to build up more mayo under the oil cap, and as I mentioned above, reached operational temperature on each drive that day. So it's not a problem with failing to reach temp.

[killcrap]

Originally Posted by Bdc101

With all due respect, I don't think that's true. I've never once seen mayo before and have been wrenching for many years. I used to own several MR2s which are notorious for having long warm up times due to large coolant volume and common thermostat failures, and even when I had very short commutes and stuck-open thermostats I never saw mayo once in hundreds of thousands of miles. My 2009 Scion and skyactiv Mazda do not have this problem and have been subjected to over a year of the same commute as this BMW with no sign of mayo.

Also, this car only took one day to build up more mayo under the oil cap, and as I mentioned above, reached operational temperature on each drive that day. So it's not a problem with failing to reach temp.

Look at my glass of water, it looks like I need to do an oil separator.