The Positive Crankcase Ventilation (PCV) system minimises hydrocarbon emissions by drawing a fresh air through the air cleaner, passing it through the crank case, mixing it with blow-by gases, taking it to a PCV valve where intake manifold vacuum is used to draw the vapors in. The make up of this system entails the fresh air inlet hose, the PCV valve and the PCV hose connecting this valve to the intake manifold while to ensure that oil does not get into the valve, there is a crankcase vent oil separator. Fresh-air inlet hose and PCV hose should be periodically checked for signs of damages; blockages or failures should be compensated by a new hose rather than by simple washing. On the four-cylinder models, fresh air inlet hose is between the air intake duct and crankcase and should be disconnected and checked for sign of wear and tear, while PCV hose should also be checked for leakage. The crankcase vent oil separator is located behind the exhaust manifold and can only be accessed by removing the catalytic converter and the exhaust manifold, then detaching the PCV hose and cleaning the separator. V6 models have an additional fresh air inlet hose that connects to both the front and rear valve covers and the hoses especially the PCV hose should be well directed when removing and fixing. The PCV valve, which may need different procedure for the models after 2004, should be replaced if it has been removed; the crankcase vent oil separator needs removal of the intake manifold and front cylinder head for accessing it in early models, with the cleaning of the area and Ensure that the gaskets and bolts are clean and are put back correctly.
