Positive Crankcase Ventilation (PCV) System
WARNING: This page is about a different car, the 2006 Mercury Mariner and 2006 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
The PCV system:
- uses intake manifold vacuum to ventilate blow-by fumes from the crankcase.
- returns the fumes to the intake manifold for combustion.
The PCV valve:
- varies the amount of blow-by gases returned to the intake manifold based on available engine vacuum.
- prevents the entry of combustion gases backfiring into the crankcase.
The PCV system consists of the:
- crankcase ventilation tube.
- positive crankcase ventilation valve.