PCV System: Description

A closed crankcase ventilation system is used to prevent crankcase fumes from entering into the atmosphere. The system consists of an oil breather fitted to the valve cover or crankcase cover. A wire mesh screen flame arrester is located in the breather cap.

A purge tube runs to the intake manifold, with an orifice or restrictor to limit the air flow. The crankcase fumes are vented to a charcoal canister when the engine is not running.