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Positive Crankcase Ventilation: Description and Operation


All engines produce small amounts of blow-by gases which seep past the piston rings and into the crankcase. These blow-by gases are a result of the high pressures developed within the combustion chamber during the combustion process, and contain undesirable pollutants. To prevent blow-by gases from entering the atmosphere while allowing proper crankcase ventilation, all engines use a PCV system.