Contour V6-153 2.5L DOHC VIN L SFI (1997)
Positive Crankcase Ventilation Valve: Description and Operation
PCV Internal Drawing
PURPOSE
The Positive Crankcase Ventilation (PCV) system is a closed ventilation system that is designed to prevent crankcase fumes or combustion gases
from escaping through the engine oil filler cap to the atmosphere and prevents backfire from traveling into the crankcase.
OPERATION
The crankcase control system controls these fumes or vapors (blow by) by directing them back into the engine where they are consumed in the
normal combustion process.
The crankcase ventilating vacuum source is the upper intake manifold.
The fresh air passes through the engine Air Cleaner (ACL) and then through the crankcase ventilation tubes which connect to the valve covers.
Ventilating air moves through the crankcase ventilation tubes and down through the oil return passage into the lower crankcase.
The air and crankcase gas mixture flows from the crankcase through the oil separator and oil separator hose to the PCV valve and then into the
upper intake manifold.