Positive Crankcase Ventilation: Description and Operation

Positive Crankcase Ventilation System:

PURPOSE
The Positive Crankcase Ventilation System prevents air pollution caused by blow-by gasses being vented to the atmosphere.

LOCATION
The PCV valve is on the back of the intake manifold.

OPERATION
The system consists of a sealed oil filler cap, rocker covers with fresh air inlet, connecting hoses, PCV valve and air intake duct. At part throttle, blow-by gas is drawn by strong vacuum into the intake manifold through the crankcase connecting hose and PCV valve. Fresh air is introduced into the crankcase through rocker cover connecting hoses. During boost conditions, part of the blow-by gas flows into the air intake duct through the connecting hose and then into the engine through the throttle valve.