Pcv Valve
The positive crankcase ventilation valve, most commonly called thePCV valve, is the outside link between the crankcase-the lower side of the engine block-and the intake manifold of your vehicle. This valve controls the flow of blowby gases, a byproduct of the air-fuel combustion, into the manifold, so that they can be re-burn during combustion. After miles of service, it is possible for the valve to become clogged and, sometimes, just stop working altogether. Here, you can follow this simple guide to help you troubleshoot the PCV valve in your car.Locating the PCV ValveThecrankcasevalve may be on the valve cover, on top of your engine, mounted on a rubber grommet. On some other vehicle models, you can find the valve on a breather opening, right on the intake manifold, or even on one side of the engine block, just bellow the cylinder head. The PCV valve itself is a small cylinder tube about the size of a small spark plug. Some PCV systems, though, may use a small plastic block that works just as a regular valve. You may see one or more rubber hoses connecting to the valve.Testing the PCV valveAlthough there are different ways totest the valveitself, the method shown here is a rather simple and quick procedure. Disconnect the valve from the grommet or one of the rubber hoses leading to the valve cover or engine crankcase. Don't disconnect the other hose that leads to the intake manifold. If your valve has a cylinder configuration, shake it with your hand and listen for a rattling sound. If the valve rattles, it is still in good condition. Otherwise, replace it.If your valve has a square configuration, make a note of the hoses connected to it and carefully pull the hoses off the valve. Look through the valve's orifices and make sure it's free of dirt and sludge. You can use carburetor cleaner, if necessary, to remove deposits from inside the valve. However, make sure to use safety glasses and chemical resistant gloves when handling the cleaner. On the other hand, you may decide to simply replace the valve, since they are rather inexpensive. Reconnect the hoses to the valve, except the one leading to the valve cover or engine.Testing for Air FlowTo test air flow through the valve, start the engine and let it idle. Make sure the end of the valve leading to the intake manifold is still connected to the hose. Then, block the other end of the valve with one of your fingers. You should be able to feel vacuum pulling on your finger through the valve's orifice. Also, the engine speed should drop about 40 to 80 rpm.If you can't feel vacuum or notice any difference in engine speed, the valve and/or hose leading to the intake manifold might be filled with dirt or sludge. Clean and thoroughly inspect hoses, grommets, fittings and other connectors for damage or tears. Replace the valve and other damaged components as necessary. However, if you noticed a slight drop in engine speed as you blocked the end of the valve and the engine began to run smoothly, the valve might be stuck in the open position. Replace the valve.Even if your PCV valve passed this simple test, it's important for you to check the valve, hoses, fittings and other connectors from time to time. Once air flow between the crankcase and intake manifold becomes restricted due to sludge or finds a different path because of damaged components, sludge will begin to cover internal parts, accelerating wear and affecting engine performance. On the long run, a properly maintained PCV valve and system will help extend the service life of your engine.
