PVC & Crankcase Ventilation System: Description

Crankcase ventilation systems are designed to prevent contaminating hydrocarbons from escaping to the atmosphere. This is accomplished by routing vapors from the crankcase through a vacuum-controlled ventilating valve (PCV Valve) into the intake manifold. In the intake manifold, the crankcase vapors mix with the air/fuel mixture and are burned in the combustion process. PCV systems are used on all 4.2L and 5.9L engines. 2.5L and 4.0L engines do not employ PCV systems, instead they are equipped with a Crankcase Ventilation System (CCV). The CCV system performs the same function as a conventional PCV system, but does not use a vacuum controlled valve.