Yellowish residue in engine oil cap

[baldyman]

checked my oil and there is a thick yellow/beige gunk in the engine oil cap. a lot of it. cleaned it out last not and it was filled with it again today after driving less than 100km. looked closer at the dip stick as well after i topped the oil up and it looks like there is water or something mixed with the oil. dipstick was halfway down and i put a little of oil in. now the oil/water is far above the hash marks on my dip stick. it has been very cold (-15C today) and snowy, if that has anything to do with it.

any ideas what the hell is going on?

[Raptor05121]

How often do you drive your truck a week and how long are those trips?

It is obviously water (condensation). When it is on the bottom of the cap, it is called mayonnaise (for obvious reasons). Usually this is due to short trips in which the engine does not reach its full heat cycle to burn off the natural condensation in the engine. You have to determine how much water is in your oil. If you are close to an oil change, go ahead and do it. If all 6 quarts is mayonnaised-up, you've got a bigger problem (gasket leak, etc). If the oil is perfectly black, then you know its just what I described above.

[lee reece]

Had you checked your antifreeze before cold weather or added water to system? You might have cracked block or ? 2007 F150 XLT FX2 SPORT - 5.4l 3V 3.73 LIMITED SLIP EDGE/EVOLUTION PROGRAMMER

[Raptor05121]

Possible as well. Gotta check the oil

[Ford Fan#1]

Mine did the same thing but it was from sitting for a month and getting driven about 5-10 miles

[baldyman]

i drive 33km to work every day (and back, of course). thats at ~90km/h avg. i think an oil change is what i will do.

added coolant in august, but havent touched it since and its still where it should be.

thank you for the fast and detailed responses, by the way. i really appreciate it

[Jersey_Joe]

Well. The professor gave the best explanation. As always of course. I'm only stating this because it happined to me. Got the mayo under the cap and shortly thereafter I found out it had a bad head gasket. But go through the process to make sure

[baldyman]

alright, thanks joe. i'll post on here when i find out something new