Positive Crankcase Ventilation: Description and Operation

PCV System:

PURPOSE
The positive crankcase ventilation system prevents crankcase vapors from escaping into the atmosphere.

CONSTRUCTION
Hoses link the crankcase to the throttle housing and the calibrated orifice in the intake system.

OPERATION
Blowby gases are drawn from the crankcase through the calibrated orifice into the intake manifold and burned. During part throttle operation the crankcase is ventilated through the oil separator (11) and the calibrated orifice (8) in the intake manifold at the ventilation hose (7). During full throttle the gases flow through the crankcase to the valve cover, past the oil separator and into the throttle plate housing where they are introduced into the intake system.