Positive Crankcase Ventilation
WARNING: This page does not describe the selected car, but rather 31 other vehicles, including the 2003 Mercury Sable, 2003 Mercury Mountaineer, 2003 Mercury Marauder, 2003 Mercury Grand Marquis, and 2003 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION:
DO NOT remove PCV system from engine. Removal of PCV system will adversely affect fuel economy and engine ventilation and result in shorter engine life.
The Positive Crankcase Ventilation (PCV) system cycles crankcase gases back through the engine where they are burned. The PCV valve regulates the amount of ventilating air and blow-by gas to the intake manifold and prevents backfire from traveling into the crankcase. The PCV valve is designed with a quarter-turn cam-lock thread at one end to prevent accidental disconnection from the valve cover.