Can someone please explain this substance? I’m using Mobil 1 10w40 and my coolant level is constant.
It has a slight fuel smell and a very soft margarine texture.

 

Hi Jason,
that is usually caused by condensation. being in the air/oil seperator you will get quite a bit of moisture in that area. more or less depending on climate and vehicle use. the water droplets mix with some oil in the area and cause this slight milkshake foam
Sean

 

Happens when your car hasnt gotten to operating temperature and stayed there for a bit. Thats moisture in the oil. Not a big problem.

 

and especially if you've had part of that warm front, then got hit by the cold front. If the dipstick is clean, you're good.

 

Thanks for the piece of mind everyone! This is my first winter actually driving this car.

 

Do you have any cooling issues, unexplained coolant overflow, or signs of oil or frothing in the coolant reservoir? Those would suggest the goop is not just from condensation.

 

Looks like someone was eating a Philly Cheesesteak around there and spilled some!

 

Yeah I get some of that in my oil cap also, after a long drive it goes away. I usually try to soak up any moisture in the cap and AOS tube with some paper towels if I am just messing around in the engine bay.

 

Yea, i've had the same crap in my jeep using mobil 1. Right now the weather is warm-freezing-warm-freezing, so the condensation really builds up.

 

Just checked the oil in the wife's car the other day. Mercedes also reccomends Mobil 1 and I found the same stuff on her oil cap. She freeked, but we have been having the same type of weather Doc was talking about. I cleaned out the cap, took it for a long drive popped the cap when we got home and no gunk.

 

Yea, I noticed with longer drives, it is all gone, but on short drives it builds up. Wipe it out, and a few more short drives and it comes back. No biggie. Spring will be here soon enough I hope

 

Craig, she just wanted a new car!

 

^^^ Well if thats the case she is a little pissed now. HEHEHEHE. Maybe that explains why it's been a dry week so far???

 

I think the correct term would be emulsification.