[Rango CK]

I recently saw something that you should replace the pcv valve with a one-way type filter. Reason being the pcv valve puts hot air back into the engine? Anyone know about this? Not sure if it would even make any difference.

 

[immattj]

Isn't the PCV valve basically a one-way check valve? And if you replaced it with some type of filter, manifold vacuum would still be sucking hot air from the same source, right?

 

[9t9-5.2]

The PCV is a one-way check valve. The valve allows blow-by in the crankcase to be pulled out by the engine vacuum. The check valve closes if the engine backfires, preventing the pressure from the backfire of blowing out gaskets.
It is an emision control device.
For most street engines, there is more benefit to running one.