Crankcase Venting.
jafo
Old Time Jeeper
I just got done with a rear main seal today. Drove it, then parked it for 30 minutes and found a small drip on the floor. It vame from the drivers side rear. The entire pan was dry as a bone but above it the backside of the block is lightly coated in oil on both sides of the block. I believe it to be the valve cover gaskets causing this. But it got me to thinking if the crankcase wasn't venting properly, it may push oil pass seals. So I pulled the hose from the oil fill tube breather that goes to the air cleaner. I started the engine and got very little if anything coming out. When I increased the rpm's, it actually got vacuum. Is this the pcv valve at work on the other end of the manifold? It's a '79 AMC 304 .