Yellow slime in oil fill area.

[Pooch]

Ok, I own a 96 328i with 140,000 miles on it. It’s cold out (right around freezing) and I have been driving it about 25 miles (highway) one way every day for 2 months now and the last time I changed the oil in it I noticed a yellow gunk build up on the oil fill cap and all around the rim of the oil fill area. I am using 5 W30 Castrol GTX high mileage, what is this build up? There has been no hard driving either. ~Tyson

[beatniks325]

kinda sound like it is from the opposite of running it too hard; too much low rpm daily driving can deposit gunk and condensation on the oil cap.

[Pooch]

I guess thats how i drive. I really like low rpms. The reason i ask is because i've been hearing stories of cracked head gaskets and such. I'll try to keep my car at higher rpms. See how that works out.

[frost dxb]

I guess thats how i drive. I really like low rpms. The reason i ask is because i've been hearing stories of cracked head gaskets and such. I'll try to keep my car at higher rpms. See how that works out.

If you do have a leaking gasket check your coolant every now and then if the level is going down and if so yes your head gasket is bad.

[hellrot325]

kinda sound like it is from the opposite of running it too hard; too much low rpm daily driving can deposit gunk and condensation on the oil cap. Not so much low RPM driving, its short trips that don't allow the mottor to get to temp. Certainly in 25 miles that isn't the case