Use the following procedure to check for correct crankcase ventilation system operation:

1. Remove the PCV valve from the engine. Leave the vacuum hose connected.
2. Run the engine at idle.
3. Place your thumb over the end of the valve to check for a vacuum. If there is no vacuum at the valve, check for plugged hoses, a plugged manifold port, or a bad PCV valve. Replace any plugged or deteriorated components.
4. Turn the engine off and remove the PCV valve. Shake the valve and listen for the rattle of the needle inside the valve. If the valve does not rattle, replace the 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 air cleaner and drawn into the engine through the 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.