Use the following procedure to check for proper Crankcase Ventilation System operation:
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 air cleaner and is drawn into the engine through throttle body.
Proper operation of the PCV system is dependent upon a sealed engine. If oil sludging or dilution is noted, and the PCV system is functioning properly, check the engine for possible causes, i.e. a missing oil cap, or dipstick, infrequent oil changes, or an internal coolant leak. Any problems must be corrected in order to ensure that the system functions as intended.