Positive Crankcase Ventilation Valve: Description and Operation

PURPOSE

The Positive Crankcase Ventilation (PCV) valve is designed to meter blow-by gas into the intake manifold.

OPERATION

The Positive Crankcase Ventilation (PCV) valve contains a spring loaded plunger which is "seated" when the engine is Off. When the engine is started, manifold vacuum lifts the plunger from it's seat and allows blow-by gasses to flow from the crankcase and into the intake air flow.