Hi guys,

After about a 2 hrs drive, I checked my oil level today and I had to add a quart of oil (Mobile 1 0W40) to my 2004 E320 (110k mls) today.

The oil cap was covered inside with a light brown creamy “foam”.

Any idea what that could have been?

I always had the car serviced at MB and this was the first time I saw this kind of foam.

Water? Head gasket?

Thanks for your input!
Dragan

PS: The cars runs just fine no noise nor any other issues.

light brown foam means water in the oil. Start by changing the oil and hope for the best. If it's the head gasket you will see the water level going down in the radiator.

As stated, probably a head gasket. If you do not smell the anti-freeze with a white mist coming out of the tailpipe, it probably blown from a water jacket passage to the oil passage nearby.

I have had this type on one of my Vettes and one of the Alfas in years past.

If you have a large increase in the water in the oil, then it probably has blown from the water jacket(s) to the cylinder (s). This type of blown head gasket will come out the tailpipe. Yes, you can smell it.

Steve Hurt

Yes, water and oil makes brown foamy oil.... Don't wait, brown foamy oil does not lubricate well.

At the dealership I would see this often in the winter. It is most likely just from condensation. If the coolant level has remained stable I would not be concerned.

Thanks to all for the input!!!

- Not what I was hopping to hear.

I spend last week in Boston driving from the hotel to work for only 5min each way, at 15F. Hence, condensation crossed my mind as well.

A few more questions, how can I determin which cyclinder bank it is (V6), should I replace both head gaskets ($33 each at autohausAZ.com) and at what cost would you estimate the work?

Thanks,
Dragan

I would change your oil, top off the coolant and drive it like normal. (dont baby it) Every couple days monitor the oil and coolant levels. If they change you may have an issue.
As for one or both head gaskets-do it right and change both little bit more work but worth it.
Cost if you do it 250 all said and done for most v6 engines -buy a head gasket set, oil, coolant, and other stuff
Cost at a shop no clue, I cant afford that

The brown foamy stuff is indeed an oil/water mixture, and it's most likely a sign of too much driving around town and too little distance driving, where the engine comes to full operating temperature for an extended period of time. What you're seeing is most likely the result of combustion byproducts mixing with the engine oil because the engine hasn't had a chance to burn them off. If the oil level was low, it's likely that's all it is, because a leak bad enough to emulsify the water and oil would cause a pretty big rise in the oil level, not a loss of volume. Besides the head gaskets, you'll need intake gaskets, exhaust gaskets, oil, filter, valve cover gaskets, oil, coolant, and cylinder head bolts. I'm guessing more than a full day's labor, as well as an assortment of special tools will be required. Replacing the head gasket on a late 90s straight 6 in a car similar to yours is about 2500 bucks, and that's if the head is straight and uncracked.

The Cap'n

Thanks guys - I just love this club and the willingness of the people to help!

Water level looks OK. But I will follow the advice and monitor both the next few days. I guess/hope it was the 5min rides last week at 15F.

Dragan