Positive Crankcase Ventilation Valve: Description and Operation

PURPOSE
The Positive Crankcase Ventilation (PCV) Valve is used to meter the amount of blow-by vapors that flow from the crankcase into the intake manifold.

OPERATION
The PCV Valve contains a spring loaded check valve that controls the amount of blow-by vapors reintroduced into the intake manifold. The valve passage size varies with intake manifold vacuum and crankcase pressure.