Material precipitating in Oil Filler cap
 

Thanks for the answers on my last post. I have a 2000 Chevy Tahoe and I noticed an off white material in the oil filler cap. It looks like white lithium grease but it's not greasy to the touch. This stuff was also in the oil breather line attached to the left valve cover. I read recently that this deposit is somewhat natural in some older model Tahoes because of condensation in cold conditions. Is this from anti freeze or ???.
Note: Didn't notice and water in the oil at last oil change
Thx for your help
BA

That would be my guess. Check the anti-freeze level, are you having to add, and also the oil dipstick, is it overfull?

Is it dexcool anti-freeze? My experieance is brown crap in the radiator with glycol (green)

if you drive only short trips sometimes the condensation will form that white sludge due to the fact it doesn't heat up enough to evaporate

Condensate would be my opinion as well...

My 99 was leaking rad fluid into the oil pan. But not enough to discolor the oil one itty bit.
Anyways, the 5.7's of that era were notorious for intake gasket failures.
Some will leak into the lifter galley, some will leak to the outside.
I too had condensation on the underside of the oil filler cap. I never did have milky oil, but radiator fluid was getting to the oil pan.
Go ahead and touch the condensation under the cap with your finger, then taste it and spit. If you have a rad fluid leak, it will taste sweet.
If it is tasteless, it is regular straight water condensation due to not running the engine at full operating temp long enough to get rid of it.

I could taste antifreeze condensed to the inside of the oil filler cap.
And all condensation went away after replacing the intake manifold gaskets.

Thanks !
I'll give it the old taste test
Just changed the oil two days ago and I didn't see any evidence of anti freeze..not tosay
it's not present. Good point though

dexcool isnt sweet