Positive Crankcase Ventilation: Testing and Inspection

PCV System:

PCV VALVE CHECK
1. Remove one PCV valve from molded hose at rear of engine.
2. Place finger over end of valve and check for vacuum. If no vacuum is present, check for plugged hoses and/or manifold port.
3. Repeat for other PCV valve.
4. Turn engine "OFF", remove valves one at a time, shake and listen for "rattle". If valves do not "rattle", or are clogged, replace the bad valve.

PCV SYSTEM FUNCTIONAL CHECK
1. Check PCV valves for correct application.
2. Engine at normal operating temperature.
3. Block off PCV system fresh air intake passage.
4. Remove engine oil dip-stick and install vacuum/pressure gauge in the dip-stick tube.
5. Run engine at 1,500 rpm for about 30 seconds and note reading on vacuum/pressure gauge.
^ If a vacuum is present, PCV system is functioning normally. No vacuum indicates a plugged PCV system or engine may not be sealed. Check for leaking valve cover gaskets, oil pan gasket, etc.
^ If a gauge registers pressure, engine is sealed and PCV system is not operating or is plugged, or engine has excessive blow-by.

SYSTEM INSPECTION
In this system, any blow-by in excess of the PCV valves capacity is exhausted into the throttle body extension and drawn into the engine. If oil sludging or dilution is noted, and the PCV system is functioning correctly, blow-by is excessive. Check for engine wear (compression check), or operation at sustained heavy loads.