Originally Posted by chadhager03

Can you really crack heads by not doing the plenum with no symptoms? I took my intake off and looked inside and there was a little brown/black on the bottom but no pooling. I'm just asking because Id rather not do something I don't need too unless something that bad is going to happen

Originally Posted by zman17

I disagree. Once the oil starts getting sucked in(even small amounts before noticeable), damage is slowly happening. If you wait until you have symptoms, it might be too late. In the form of the usual clogged cat. But, once that happens, you are running the risk of cracking the heads.

Originally Posted by HeyYou

By the time symptoms start becoming obvious, it has been a problem for a while already. Biggest trouble is the cat gets clogged, and that will do all sorts of rude things to your engine. You may not notice it until you are severely down on power, and the engine seems to want to run rather hot. The heads in these trucks weren't the best when they were brand spanking new.... stress them once to often, and its time for new ones. (which in all reality, isn't a bad idea anyway, and if I had the cash, I would put some new ones on my truck in a heartbeat. but, since I am poor, I just fixed the plenum....)

Originally Posted by jasonw

The oil from a leaking plenum gasket will, if nothing else, ruin catalytic converters and oxygen sensors. Not cheap parts to fix.

If you have anything on the bottom of your intake besides metal, either your PCV is broken, or your plenum gasket is blown (even without symptoms). You won't be able to see pooling oil from the TB unless its REALLY bad, due to the angle at which the manifold sits. It pools in areas that you cannot see without a small dental-style mirror (or removing the manifold off the engine).

I thought mine was fine to. Replaced the plenum plate and gasket as preventative maintenance, and turned out to be half a quart of oil sitting in my kegger, pooled in areas I couldn't see.