F 250 2WD Pickup V8-5.4L CNG VIN M (1999)
Positive Crankcase Ventilation: Description and Operation
PCV System Flow Schematic
Typical PCV Valve
Typical PCV Vacuum Connector
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 should be
mounted in a vertical position. On some applications, the PCV system is connected to the evaporative emission system (refer to the VECI decal).
CAUTION:
Do not remove the PCV system from the engine. Removal of the PCV system will adversely affect the fuel economy and engine ventilation and result in
shorter engine life.