I have a 2002 4.0 sohc with fresh rebuild from local shop. Motor runs greats, after about 450 miles it starts leaking oil at front and fear main seals. They have replaced them three times. I have been advised possible pcv problem. Now seeing oil film around oil fill cap too. Again motor runs great. Shop is getting truck back on Monday and keeping it until it is fixed.

How can truck run so well with pcv plugged or pinched off ?

They said something about adding something to oil to stop the leak, which I am totally against.

Has anyone had this kind of issue or do you have any ideas.

 

To much crank case psi can blow them out.