Initial Inspection and Diagnostic Overview

If an engine is idling rough, check for a clogged PCV valve. Replace if required. Use the following procedure:
1. Remove PCV valve from intake manifold.
2. Shake valve and listen for the rattle of needle inside the valve.
3. If valve does not rattle, replace valve.

With this system, any blow-by in excess of the system capacity (from a badly worn engine, sustained heavy load, etc.) is exhausted into the intake manifold and is drawn into the engine.

Proper operation of the crankcase ventilation system is dependent upon a sealed engine. If oil sledging or dilution is noted, and the crankcase ventilation system is functioning properly, check engine for possible cause and correct to ensure that system will function as intended.