03 4.0 Intake question

[ummduh]

Why would there be a oil buildup around the base of the intake at the heads on this truck?

I've been trying to think. It doesn't use/burn/lose any oil, but it does seem like the MPG isn't where it used to be. ( we did move from WI to CA, so difficult to compare the two.. used to be better in WI though) It's been acting/running "odd" for a while too. Idle in gear has been higher, among other things.

There is definitely oil buildup down there though. Do the 02+'s have issues with leaking intake gaskets? Doesn't really explain why there is oil at the intake though..

 

[rumpledoll]

Here's a guess:

A bad PCV valve. It's connected from an oil rich part of the engine to the intake manifold. It's possible that the valve is stuck wide open and letting in more oil than designed.

Rumple

 

[ummduh]

Hmm.. Yea, didn't think about the PCV valve.

I'll have to change that ASAP. We're over 60k, I'm sure it's time regardless.