How to Replace a PCV Valve

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PCV Valve Intro

The PCV (Positive Crankcase Ventilation) Valve
The PCV (Positive Crankcase Ventilation) Valve. Photo by Tegger

Your PCV valve is a simple plastic piece of plumbing that performs a not-so-vital function for your engine. The Federal government, however, thinks it's very important. In reality, it's an important part of your car's emission control system. When it's working well, you won't even know it's there, but the government does, and they want to be sure it's working at full capacity every day your car is on the road. That's why your emissions system gets so upset when the PCV valve is out of whack. So let's get it back into whack so we can move on and do some fun stuff tomorrow. 

If your PCV valve becomes clogged, your emission controls can't function fully, and the results are poor idling, loss of gas mileage, slow acceleration, loss of power and other similar ailments. There isn't a consensus on how often the PCV valve should be replaced, but somewhere in the neighborhood of 30-60,000 miles seems to make sense. We'll show you how to get it done fast and easy.

What You'll Need:

  • replacement PCV valve
  • needle nose pliers
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Locating the PCV Valve

PCV valve location
This PCV valve is slightly buried. Photo by Tegger

Your PCV valve is located someplace on the crankcase. Need more? Ok, it is a small plastic plug that is stuck directly into the top half of your engine. It will also have a rubber hose coming out of one end. In some cases, the valve will be between two rubber hoses, one which is connected to the crankcase (the engine). The valve may be hidden and difficult to reach, or it may be sitting right on top of your engine.

To be sure of the PCV valve's location, you should consult your service manual.

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Removing the PCV Valve

PCV valve installed in crankcase.
Remove the old valve with needle nose pliers. Photo by Tegger

Once you've located your PCV valve, you need to get it out. First, remove the hose that is connected to the top of the valve. If your valve is installed between two hoses, you will be able to pull the valve out. If your PCV valve is installed directly into the crankcase or valve cover, grasp it firmly with your needle nose pliers and pull it out. It should come out with a little ​oomph. Usually, it's just held in place with the tension of the black rubber grommet that links it to the engine case. 

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Installing the New PCV Valve

New PCV valve is in.
Press the new PCV valve into place firmly. Photo by Tegger

With the old valve gone, you need to install the new PCV valve. Most replacements involve only the valve itself, but sometimes a replacement kit will include new hoses. Be sure to inspect all of the rubber that connects to the PCV valve to be sure none of it is severely worn or damaged. An old, tired rubber connection at the crankcase or elsewhere in PCV-land will negate the whole job by causing the same problem you had before, but in reverse. Either way, the car will rub badly and you'll feel bad because all of your work was for nothing. If any of the rubber is worn, replace it. 

To install the new valve, first, attach the valve to its hose. This is much easier to do now than when the valve is installed in the engine. If your valve is mounted in a convenient location, just press it into place and you're done. If it's less than convenient, grasp the PCV valve with your pliers and carefully press it in.

Tip: If you're having a hard time getting the new valve to slide in, use a little motor oil as lubricant. Never use anything but oil.