LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Pontiac >> 1966 >> GTO Eng CD WS, Not Available Trans >> Repair and Diagnosis >> Engine Mechanical >> Mechanical >> Crankcase Ventilation Systems >> Operation
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Crankcase Ventilation Systems: Operation

Air enters system through a vented oil filler cap into engine crankcase where fumes are picked up and carried through ventilator valve and into intake manifold.

Ventilator valve regulates flow of fumes to intake manifold depending on intake manifold vacuum. Upon reaching intake manifold, fumes are mixed with the fuel mixture and burned in combustion chambers.

Fig 1: 1964-65 "OPEN" VENTILATION 6 CYL. 1-BBL. CARB.
G09340547Courtesy of GENERAL MOTORS COMPANY
Fig 2: TAKE-APART TYPE VENTILATION VALVE
G09340548Courtesy of GENERAL MOTORS COMPANY
Fig 3: 1963-67 "OPEN" CRANKCASE VENTILATION THREE 2-BBL. CARBS.
G09340549Courtesy of GENERAL MOTORS COMPANY