Hello Everyone,

I need some help as the weather is too bad to tear into it right now and I have had a million different opinions.

I have a 2000 Half-ton with the 360, I just rebuilt the motor from the ground up last year. Its starting to burn oil at idle though, it doesn't burn it any other time but it burns it pretty heavily at idle. I haven't been able to check cylinder pressure yet to rule out the rings, but I doubt it is considering it doesn't burn it all the time just at idle.

I have been told it could be my valve seals or plenum. I need to fix it soon and would like some direction before I start tearing it back down. Any ideas?

 

The plenum is easy to rule out, use a dentist mirror and the most powerful flashlight you can find to peer down the throttle bores and check for oil pooling in the intake.

I believe both of your suggestions would burn oil at all times though; in fact, I have never heard of an engine burning oil JUST at idle. I would think that whatever is letting oil in at idle would come into play at all rpm ranges.

 

An engine with a bad plemun gasket wiil suck more oil into the intake mainifold at idle due to the fact that's when the vac pressure is the highest inside the intake manifold. There's a lot less vac created at the higher rpms.

 

I would take a careful look at the PCV valve as well. That will suck more oil at idle than any other time...... get one from the dealer, see if the problem goes away. Less than 10 bucks, and five minutes to change.

 

^^^+1 I always seem to forget about the pcv.

 

yep, theres likely a coorelation between idle vac and oil consumption.

+1 plenum or pcv, although intake seals see alot of vac as well...