Spriro

I noticed there are some yellowish cream on my oil filler cap. (Oil filler cap mayonaise) I did some research and found out that it means there is moisture in the crankcase. The engine can't get hot enough to evaporate this moisture.
Is this normal in winter time? The temparature has been around 20F-30F here lately.

mleskovar

If you wipe off the 'cream' and change the oil (look for water/coolant in the oil) does it come back? Are you losing coolant but none of it is dripping to the ground? This is generally an indication of a leaking head gasket although there are several ways water can get into the oil supply. Disclaimer: I am not a professional mechanic (although that could be a good thing :-)).

C434ME

i just changed the oil yesterday in my C43 and noticed the same thing. I had about 4500 miles on mobil 1. I only travel about 5 miles to work everyday so the car does not really warm up all the way. Best thing to do is change the oil more frequently and drive it at full operating temp for about an hour a week on the hiqhway so all of the condensation can evaporate.

I am also going to keep a more watchfull eye on it to make sure it is not a headgasket leak.

Spriro

mleskovar

What would the oil be like if there is any water/coolant in it?
When I dumped the oil at the recycling place it looked normal. Just like regular 5000 miles used oil.

E55AMG99

If there was radiator water in the oil, it would be milky like what you are seeing on the cap. Since the radiator water is under pressure and the likely places it could leak into the crankcase are not, the coolant would eventually fill the crankcase. You aren't seeing a drop in the coolant level are you? If oil was getting into the coolant, you would see oil scum floating on the top of the radiator.

IMO, it sounds like it is condensation buildup.

Spriro

Coolant level seems to be steady.
Maybe the weather is just too damn cold here.
I noticed the temparature gauge only reach 80 max on my dash. On short trips it does not even get to that level. In spring and summer it usually goes a little bit above 80.

E55AMG99

You just need to drive you car on longer trips. Now how bad can that be?

Spriro

Not bad at all.
If only God could turn up the thermostat a little bit, it would be awesome.
It's gonna be snowing and freezing rain in the next 2 days here.

Wanna trade place? I'd love to trade to Bay area.

E55AMG99

Trade places? No way! You can come visit any time though!

Petmerctech

That stuff is emulsion and is normal. It forms when the weather is cold. Nothing to worry about.

bamberger_1

If the creamy stuff is only of small amont it is caused by the breather which sits in between the crankcase and the airfilter. It is supposed to direct the crankcase fumes into the air intake and burn it. If its very cold and/or moist the airflow may reverse when the car sits and cools down, drawing small amounts if moist air into the crankcase, which then condenses on the filler cap. Maybe a new (new gasket) filler cap could help, also there an air exchange may take place´in the cool down phase.
However, if significant amounts of coolant vanishes w/o dripping to the floor and the used oil looks milky, the posters who suggested a shot head gasket, are right.

Steve Clark

Even in Germany. The goop on the filler cap is simply normal moisture in the crankcase from blowby.There's unburned fuel as well,so the odor may smell a bit like gas.This is normal for a car that sees only short trips and never gets fully warmed up.
What is "warmed up"?..it takes at least 15-20 minutes of steady driving/not creeping in city traffic....at least twice the time it takes for the coolant temp to get warmed up into normal operating range.The definition of "fully warmed up" is a stable oil temp.
Back to the oil foam you're seeing-with short trips it'll never go away.Your current cold weather doesn't help either.
Years ago I was driving a VW beetle to work-3.5 miles each way.
The oil-filler cap's underside was nasty/ugly/foamy.If a small air-cooled engine can do that...
This is also an indication of why short trip-cycles are hard on engines.