See Figures 1 and 2
The intake manifold vacuum removes any crankcase vapors and piston blow-by from the engine. Emissions pass through the PCV valve into the intake manifold plenum. The vapors then become part of the calibrated air-fuel mixture, are burned and expelled with the exhaust gases. The air cleaner supplies the "make-up'' air when the engine does not have enough vapor or blow-by gases.
See Figures 3 and 4
To inspect the PCV valve, remove the valve from the intake manifold, then shake it. If the valve rattles, it is probably fine; if there is no sound, it must be replaced and the PCV hose cleaned by spraying solvent (such as a carburetor cleaner type of solvent) through it.
If the valve rattles, you should still check the PCV valve with the engine idling. Pull it out of the vent module and place your finger or thumb over the end to stop air flow. You should feel some suction, and the engine speed should drop slightly. If there is no suction, or if the engine idle speeds up and smooths out considerably, replace the valve. Remove the PCV hose from the engine, then inspect it and, if the inside is coated with gum and varnish, clean it by spraying solvent through it.
Check the vacuum at the PCV inlet tube, as well. Disconnect this tube from the air plenum and loosely hold a piece of paper over the tube. After a approximately one minute, enough vacuum should build up to cause the paper to be sucked against the opening with a noticeable amount of force. This test proves whether or not the suction side of the system is clear.
REMOVAL & INSTALLATION
Please Refer to General Information & Maintenance for removal and installation procedure of the PCV valve.