I was discussing my oil blow by problem (1986 F150, 5.0 EFI) with a mechanic friend and he told me there was another filter that may be causing the problem. He told me that some of the early 302's had a small (1" dia) mesh filter that was in the back of the block or the intake manifold that was part of the PCV system. They had a bad habit of clogging quickly which lead to failure of the PCV system venting properly. I have not yet had a chance to start looking, has anyone else heard of this filter?

It is appox. 1" long by 1" in dia.; thin gauge metal with a mesh screen on one end and filled with what looks like metal fitler media. He told me it fit in a block or manifold opening and was not connected to a hose.

Any help appreciated.

 

I think this problem is found in the car intake manifolds. I'm not aware of a screen being a problem on the truck EFI systems.