Positive Crankcase Ventilation: Description and Operation

Positive Crankcase Ventilation System (PCV):

^ The PCV valve is operated by intake manifold vacuum.
^ When the engine is running at idle, the valve is opened slightly and a small amount of blow-by gas is drawn into the engine.
^ At higher engine speeds, the valve is opens further and a larger amount of blow-by gas is drawn in.
^ System consists of PCV valve and assorted vacuum lines.