I drive my wife's old Pontiac as my secondary vehicle when I'm tinkering on my jeep. The car doesn't get used much and only makes very short trips. For years now, I've had milky junk on the oil filler cap but the oil and coolant are as clean as can be and its never used a drop of coolant. All that to say I just assumed the milky junk is from condensation. Maybe that's your issue too.

 

I have a brand new vehicle ( non-jeep ) .......

One day I noticed milky substance on the oil fill cap. UH OH !!!!

Drove it down to the dealer to show him and it was GONE !!!!

Like others said ..... drained oil looks OK ..... not losing coolant ...... just some condensation buildup.

Next time you see it ...... drive it for at least 30 minutes if not more and recheck.


One thing you can do ........ clean that oil fill cap, get any and all old residue out of it .... might have old crap up in there adding to your confusion.