Foamy Engine Oil

Long story short: My car suddenly has water in its oil reservoir. Question is, how did it get there: rain water got into the system when I added a quart of oil recently (seems unlikely), or do I have a leak in my cooling system?

Here’s the setup:

Prior to leaving on a 120-mile trip yesterday morning, I checked my car’s (a 1999 VW Passat, V6, 110,000 miles) oil level for the first time in a couple weeks, only to discover, when I pulled out its dipstick, what looked like a thick, yellow-y, marshmallow-y foam all over it. Nasty. Never seen anything like it. This was definitely a new problem.

Knowing very little about cars, but knowing that it was time I got an oil change anyway, I took my car into Jiffy Lube and had them flush my engine and change my oil. I then set off on my 120-mile trip and checked the oil again once I’d arrived. There was a tiny amount of very light yellow-colored “creaminess” on a couple parts of the dipstick, but it was nothing close to how bad it was earlier in the day before I’d changed my oil.

I called my local VW dealer and the guy there told me that I have water in my oil reservoir – that it could have either gotten there by mistake (rain water dripping in when adding oil, for example) or I’ve got a leak somewhere in my cooling system. He says that the fact that I’ve got almost no foam in the system after having just changed my oil and gone on a long trip leads him to think it may be the former scenario. He suggests I change my oil one more time before I head home and see if that doesn’t get rid of the foam once and for all.

The car runs fine, I’m not losing power, and my radiator fluid is the same color it’s always been (in other words, it doesn’t appear to be mixing with the oil). I’m going to take my car into the shop when I return home in a day or two, but in the meantime, anyone have any experience with this sort of thing?


I think I know less about cars, but I had the worse case part of this problem: a crack in the block causing the coolant mixing with the oil. What my mechanic told me was to keep an eye on the oil, not the coolant. If the oil started to resemble the consitency of a milkshake, the problem was about to get a lot worse.

That doesn’t sound like your problem, though.

It could be a cracked block or a blown head gasket or another major engine problem. However it could be nothing. Did the oil level on the stick raise any? As in over full? Do you normally not drive very far? In other words if the car never gets completley warmed up, condinsation could build up in the motor causing this problem. Though it sounds like water was somehow added to your system and not appered naturally. Does the temp gauge show any kind of increase over before? I would try what your mechanic has suggested, and drive it home. then keep an eye on it for the next couple of days and see if it happens again.

I have an 89 VW FOX and had a similar problem - oil creaminess - so bad that they wouldn’t change it at the local Jiff-lube. At the VW dealer, their older, experienced mechanic was sure it was all of the short trips I take (condensation). He told me to take the occasional longer trip (your 120 miles would be ideal) to “burn it off.” Everything’s been great since. This doesn’t sound like your problem (and I live in a colder climate anyway), just wanted to share a similar story with a simlilar car.

Perhaps you have an evil neighbor or vengeful ex.

As stated above, this is usually a cracked head or block, or a blown head gasket, but could also be normal condensation build up from lots of short trip driving. The thing to do it watch to see if it increases, but more importantly, watch if your coolant level decreases. Also watch for increased condesation output from your exhaust pipe, or if the exhaust takes on a different odor that smells much “sweeter”. Since you said it’s an older car with a good number of miles on it, and you said it more yellow, this looks more like a gasket failure than normal condensation buildup. Usually, if it is a gasket. block, or head failure, you won’t find oil back in the radiator, as the coolant system builds pressure that escapes out through the leak. There is really no pressure to overcome this and push oil back into the coolant system.

Repair shops can figure it out pretty quick if you don’t want to wait. They can check the spark plugs for abnormal fouling or build up, and they can do a coolant system pressure test to see if the pressure escapes anywhere into the block.

If it does turn out to be coolant getting into the engine, you need to get it fixed quickly if you plan to keep the car. The coolant causes accelerated wear on engine bearings and will cause the engine to fail much sooner.

I think if you had a cracked head or block, or even a blown headgasket for that matter you’d find oil in your coolant reservoir.
Either way find a mechanic you trust and have them check it out.

Depends on where the crack or leaky part of the gasket is located.

Where’s this new Icehole guy when you need him?

Are you blind? :)

Exactly. If you had a crack between an oil journal and a water jacket right past the oil pump, you could get oil in your cooling system. That’s one of the very few places where the engine oil pressure could overcome the coolant system’s operating pressure. The more common is a crack or gasket failure where coolant under pressure gets into an oil journal as it’s heading back down to the pan.

In any case though, it’s much easier to watch for coolant in the engine oil, than engine oil in the coolant.

Don’t VW’s have a clear coolant reservoir right by the wheel well? You should be able to see oil in it just by glancing at it.

It’s been my experience that a blown headgasket will get oil in the coolant. Not the other way around. The oil pressure in the cylinder head galleys is pretty high. Coolant leaking tends to go into the cylinder and burn. This leaves tell-tail white deposits on the spark plugs.

Now a nice healty crack in the block will give you water in yer oil. Then I’m afraid it’s time to junk her.

Either way, like I tell my customers. You should take it to a competent mechanic and let him check it out. I can’t fix your car over the phone.

Yup, they do and I don’t see any oil in it.

Having just returned from my trip (from Sacramento back down to San Mateo – approx 120 miles), I checked my oil again and there was even less of that slight yellow-colored slick (by the way, my coolant is orange, not yellow) on the dipstick than when I checked it up in Sac. In addition, the car continues to run well (no knocks, pings, smoke, or smelly exhaust) and at its normal temperature. Still, I’m assuming the worst for now since I’d rather be pleasantly surprised by good news than frustrated yet again by bad. I plan to call my mechanic in the morning and schedule an appointment. I’ll let ya’all know what he has to say.

Thanks for the tips, everyone!


Dude, Vede Dude, blown head gasket, sorry…
Takes a few hours to change, will cost more than a grand unless you do it yourself.

A head gasket is the gasket that goes between the cylinder head and the block. It makes sure that the oil stays where it belongs and the coolant stays in it’s respective galley ways. When they mix, the only real culprit can be this gasket because it’s the only place in an engine where they both flow using the same material.

Yipes, that sucks, been there, changed that…

To echo others, yes – it’s most likely a head gasket. Not an uncommon repair to do at 110k miles. It will most likely cost around $1000 at a shop, but they’ll take care of a few other things while in there (water pump, timing belt if applicable), so it should be good to go for a while after that.

If you car is still behaving properly, you can let it go a bit longer. Keep an eye on that temp gauge, though! Overheating is a very common side effect of a blown head gasket. I’m not a VR6 expert, but if they have aluminum cylinder heads, overheating them will possibly cause them to warp. That will turn your $1000 HG job into a much more expensive job.

Personally, I’d get it figured out ASAP and perform the repair at a good shop. Your Passat should have many good miles left on it. Oh, and if you have an automatic transmission, get the fluid changed while you’re at the shop (<$100).

Leaving the water\oil mixed in the engine is a bad thing. Rust and all that. You also will polish the walls of the cylinders and possibly have Ring Failure because the oil is diluted with water and it isn’t properly lubricating the cylinder wall.

Not to mention rod bearings, and camshaft lobe scoring.

Cylinder wall damage just means you now have a good excuse to bore out your engine. :D

30 over baby, 30 over!!! Opps, sorry, just remembering what happened to my 76 Buick 350.

I take it from your entry on, that indeed, the problem was something major?

He hasn’t bothered telling us what happened. :PPPP

possibly unrelated, but I remember hearing that VW (and by extension Audi) had some major problems with one of their engines - the oil could get “sludgy” and could eventually get clogged somewhere in the system causing a lot of damage even on relatively new cars.