While I was changing the oil in my '04 F-150 (5.4) this weekend, I noticed some light yellowish/beige colored substance under the oil cap and inside the oil filler neck. The texture was almost grease-like and I'm not sure what it was or if it's harmful. The quantity was approximately 1-2 tsp - not a lot, but I've never seen this before. The truck had just returned from a 15 mile trip to run a few errands, so the it was at operating temp. I've always changed the oil every 3000 miles w/Ford 5W-20 semi-syn. Truck drives great - no issues. 21,000 miles.

Any help as to what this substance was or if it's harmful would be helpful.

E

 

It's just a little moisture in the oil. It can create a froth if you make lots of short trips, especially in colder weather. A good long 40-50 mile run will evaporate it all off. But it's normal and expected in all engines.

 

Thank you, RockyJ.

I should have mentioned that when I drained the oil, it looked perfectly normal. No antifreeze or any of the froth.

Thanks again,
E

 

i have the same problem, i wipe it out every week or 2 just to make sure none gets down into the valve covers


as far as i can tell its only in the filler neck anyway

 

A good 30 minutes with the engine running at full operating temp should evaporate it all off. Lots of short trips aren't good for these motors.