PCV System: Operation

At part throttle, blow-by gas from the crankcase is drawn into the intake manifold through the rocker arm cover connecting hose of cylinders 2 and 4 and the PCV valve. At the same time, fresh air is drawn into the crankcase through the air cleaner and rocker arm cover connecting hose of cylinders 1 and 3, and routed to the intake manifold along with the blow-by gas.

At wide open throttle, when intake manifold vacuum is low, the blow-by is directed into the air cleaner through rocker arm cover connecting hose of cylinders 1 and 3, and is drawn into the carburetor.