The Positive Crankcase Ventilation (PCV) system is a very important in minimizing hydrocarbon emission by evacuation of crankcase full of unburned hydrocarbon fumes. On a four cylinders the system comprises a single crankcase ventilation hose that sucks in crankcase vapors through the vent housing installed on the under part of the valve cover and then channeling the vapors into the air intake duct before entering the combustion chambers. For V6 models, there is a fixed orifice on the front valve cover; two hoses control the air fresh and crankcase vapor with regard to intake manifold vacuum. Deterioration of PCV system is not good for the engine; therefore, one should check the hoses for the crack or any obstruction and to clean or replace as the case may be. Approxations of both of these problems may include a rough idle as well as stalling, or the presence of oil leaks, and in interpretation of a leakage sign, there may be rough running or high idle speed. A functional check on V6 models involves a removal of the end of PCV hose, the starting of the engine and checking for vacuum. In case of a higher crankcase pressure that is above the expected limit then it is advised to be checked by an expert. In cases of heavy sludge or oil dilution, more tests are required. In case of component exchange, it requires removal of hoses and conditioning or replacement of vent housing, fixed orifice, however, vent housing is molded in the valve cover and cannot be replaced independently.