Defective PCV causes on engine functionality:
A neglected PCV system will soon fail to function, and the result can be expensive as well as troublesome for the car owner. If the crankcase is not adequately ventilated, the motor oil will become contaminated, and heavy sludge accumulations will begin to form. Internal parts, not protected by the motor oil, will start to rust and corrode due to the water and acids that will become trapped within the crankcase.
If the PCV system is not functioning properly, the flow of crankcase vapor into the intake manifold will not be correctly metered. This, in turn, will upset the fuel/air mixture for combustion and can cause rough idling or even stalling of the engine. Furthermore, intake and exhaust valves, in addition to sparking plugs, may eventually be burned and rendered useless, prematurely affecting performance and requiring expensive repairs. To assure trouble-free performance of the PCV system and, in turn, the engine and vehicle, routine maintenance of the PCV system are recommended and required.
Symptoms of a Bad PVC
Increase in internal engine pressure
Failure of one or more oil seals or gaskets
Engine oil leaks
Moisture and sludge buildup inside the engine
Engine surges and possibly black smoke
If the PCV valve gets stuck open, or a system hose gets disconnected or rupturedâproducing a vacuum leakâyou'll notice one or more of these symptoms.