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Contaminated Engine Oil (creamy)

5294 Views 8 Replies 6 Participants Last post by  albertm1
Vehicle: 1998 E320 with ~80k miles. The oil filler cap appears to accumulate moisture and eventually becomes covered (on the inside) with a 1/4" layer of disgusting creamy oil. It is easy to wipe off, but I'm concerned that the breather system is not working. I have checked the rubber hose leading from the left valve cover across the back of the enginer to the air intlet track just down stream of the mass airflow sensor: it is free of obstructions.

So, has anyone else had this problem? javascript:AddText('[?]');

I'm even considering changing the angle of the port at just downstream of the MAF to create more vacuum. However, this is a unmodified car and all should be well. Very odd.
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If the oil is that creamy you may have a head gasket that is blowing coolant into the oil galleys.

There's no way that a properly functioning engine should be picking up enough moisture that the oil gets creamy.

The immediate problem is that creamy oils lose their ability to protect the metal surfaces.

You need to get the cooling system pressure tested.

What leads you to the crankcase ventilation system?

I suppose you could quickly and inexpensively buy a PCV valve....

After running a while does it get more? or less creamy?
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Do live in a cold climate and/or frequently make short trips? It's perfectly normal for there to be some water in the oil in a healthy engine in cold weather. Water is a byproduct of combustion and can condense in crankcase as the oil cools off. The water normally evaporates when the oil heats up and exits through the PCV, but if you drive short distances, the oil never gets hot enough to boil off the water. A long drive (100+ miles) should clean out any condensation.

I've noticed the same phenomenon in my car in the winter, although I don't think I had 1/4". Beyond trying a new PCV valve, I don't think you should worry about it, unless you start seeing it on the dipstick or in the oil when you drain it. (If it's a head gasket, it will get progressively worse with time.) See if it goes away after a long trip or warmer weather.

You may be interested in a similar discussion w/ photos on a BMW forum: (The cream I've noticed under my oil cap is a much lighter hue.)

If you actually do have a bad head gasket or cracked head, you should see other telltale signs:
  • oil droplets in the coolant[/*]
  • decreasing coolant level[/*]
  • increasing oil level[/*]
  • white exhaust that smells like antifreeze[/*]
Hope this helps
Hey guys thats how our cars have it, if the climate changes from cold to warm or warm to cold really fast like in Ny during winter and you dont use your car too much thats whats going to happen on the oil cap. Its not a head gaskiet if it was you would have the same thing on your dipstik.
Thanks for the advice, guys. I have checked the oil each time I changed it and I have also checked the radiator for contaminants. So far, nothing. It appears that the motor oil is fine, it just accumulates a lot of condensation at the top of the engine. I do live in Iowa (chilly) and it does run for a while in the mornings to warm up. With that said, I would still expect the ventilation system to be able to take care of this issue. I’ll keep working on it.
I have had this problem too. I hope it's nothing.
I think it might also have something to do with not putting the MB recommended oil - 0W. My mechanic accidentally put in some 10W and that's when this happened.
Anyone else think so?
Nope its not that. Its how the V6 engines are. Both my E240 and C240 has this in the winter. IF you check when the car has yust heated up its the creamy Caffe latte look under the oil filler cap. IF You check later its gone.

Nothing to worry about.
Not sure if we're talking about the same thing - the initial poster and I both have what looks like a wad of orange mayonnaise glopped on the oil cap. The oil basically emulsified with water I assume and formed this stuff.

When I first got it I was on a long road trip like 1000 miles from home and freaked out cuz I thought I blew a gasket. I pulled into a gas station cuz the low oil warning came on - popped open the cap and yuck. I cleaned it off and added another quart and the goop didn't come back, thank god. But it was wierd.
I asked my dealer about it. They repeated what was said you earlier: its normal, don't worry about.

Okay. I'm happy. Thanks again guys.
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