Water in the Oil

[SpecM]

Crap on my life, I've been finding water in my oil recently, and I'd really rather it not be there :( I've changed my oil twice, once to my regular Castrol GTX 20w-50, this last time switching to Shell Rotella 15w-40. Water is mostly noticeable as milky residue under the oil cap.

Checked the compression, about 130psi, varying only 10psi lowest to highest, and no oil or HCs present in the coolant, which rules out a head gasket problem. That is, it does in my mind. No coolant or oil loss either. Any thoughts on this?

I'm thinking that the problem is condensation, since I've found water in the throttle body and intake boot as well. How do I rectify this? Does anyone else have this problem?

[jlevie]

Finding a milky emulsion under the oil filler cap in cooler weather is quite common and only means that the car is being driven hard enough or long enough to boil out the blowby condensates. It takes 20-30 minutes of sustained highway speed driving in cool/cold weather to get all of the engine up to the temperatures required to boil off the condensates. An urban cycle with lots of short low speed trips won't ever get the engine hot enough.

[slo325i]

Worst case of scenario= cracked block. If the head's in good condition, just replace the block. Hoping it's not the case though. Good luck.

Justin

[NC325iC]

probably just a little condensation, i get a little bit of what i can only guess is steam when i open the oil cap on a hot engine. moisture from the air getting in while the car is sitting and condesing on the cold metal of the engine

[SpecM]

I suppose, but how do I fix this? I'm worried about contamination...

[NC325iC]

i dont think it will cause contamination, once the engine is hot itll boil the water and it will be sucked out via vacuum. and if your engine is oiling things properly the water shouldnt be able to get in contact with and bare steel.

how much water do you think is getting in? condensation wouldnt produce a whole lot of water.

[JonFreyr]

Milky residue isn´t that big of a deal, sign of short trips in colder weather. I have this exact same "problem" and have done extensive searching and spoken to a BMW mechanic, was told that this isn´t worth losing any sleep over....if compression in OK and the engine runs as it should then you should be fine. However, an oil analysis is a realtively cheap way of finding out whether you have an actual problem.

[jlevie]

Correct! The cure is taking the car out for run once or twice a week and running it at highway speed for at least 20 minutes along with a shortened oil/filter change interval. In cold weather an urban driving cycle means no more than half of the normal intervals between oil/filter changes.

[drift]

I had that similar milky oil-cap once , it was just cold winter moisture.
Runs and drives great.
No steam, no smoke.

[SpecM]

hmm, I guess I let it go then

good call on changeing the oil more often, will do