Purpose

A Positive Crankcase Ventilation (PCV) system is used to consume crankcase vapors in the combustion process instead of venting them to the atmosphere. In gasoline engines, small amounts of combustion gases leak past the piston rings into the crankcase. These crankcase blow-by gases contain undesirable hydrocarbon air pollutants. The PCV system is used to prevent these vapors from escaping into the atmosphere, while allowing proper ventilation of the crankcase to maintain good oil quality. Fresh air from the air cleaner is pulled into the crankcase, mixed with blow-by gases and then purged through the Positive Crankcase Ventilation (PCV) valve into the intake manifold.