A PCV valve works to pump the blow-by gases out of the crankcase to the intake manifold which is combusted in the cylinders; it is a PCV valve, an oil separator, and connecting hoses. Air comes in through the air cleaner to the rocker cover is ventilated, and flows to the oil separator, and then to the PCV valve, which functions as per air pressure variations between the intake manifold and the rocker cover. The PCV valve is also important because it controls the amount of gas that is re-introduced into the combustion chamber; it also partially closes at low engine revolutions to restrict the amount of gas flow and opens further as the engine speed rises. A valve blockage will not allow the gases to escape the crankcase resulting in pressure build-up that can cause the gases to escape through weak seals or gaskets resulting in oil spillage and formation of sludge. To test the component, disconnect the hose of the PCV valve, turn the engine to 700-1000 rpm and put a finger on the end of the valve to test the presence of a vacuum; in the absence of this, the valve must be changed. To remove, install, discharge the hose, unscrew the valve out of its fitting, screw in the new one, and reconnect the hose.