PCV Valve

Positive Crankcase Ventilation (PCV) valve operates in the closed crankcase ventilation system. Closed crankcase ventilation system consists of PCV valve and ventilation hoses.

PCV valve is a one-way check valve, located in valve cover. When engine is running, manifold vacuum pulls PCV valve open allowing crankcase fumes to enter intake manifold. If engine backfires through intake manifold, PCV valve closes to prevent crankcase combustion.