Crankcase Ventilation System Inspection/Diagnosis

Crankcase Ventilation System Inspection/Diagnosis

Results Of Incorrect Operation
^ A plugged positive crankcase ventilation (PCV) orifice or hose may cause the following conditions:
^ Rough idle
^ Stalling or slow idle speed
^ Oil leaks
^ Oil in air cleaner
^ Sludge in engine
^ A leaking PCV orifice or hose may cause the following conditions:
^ Rough idle
^ Stalling
^ High idle speed

Functional Check
With these systems, any blow-by in excess of the system capacity, from a badly worn engine, sustained heavy load, etc., is exhausted into the air cleaner and is drawn into the engine.

Proper operation of the crankcase ventilation system depends upon a sealed engine. If oil slugging or dilution is noted and the crankcase ventilation system is functioning properly, check the engine for a possible cause. Correct any problems.

If an engine is idling rough, inspect for a clogged PCV orifice, a dirty vent filter, air cleaner element, or plugged hose. Replace as required. Use the following procedure:
1. Remove the PCV hose from the rocker arm cover.
2. Operate the engine at idle.
3. Place your thumb over the end of the hose in order to check for a vacuum. If there is no vacuum at the hose, inspect for the following items:
^ Plugged hoses
^ The manifold port
4. Turn OFF the engine.
5. Inspect the PCV orifice in the valve cover for debris or blockage.