Your car’s engine operates by mixing air with fuel and then burning it. This obviously creates waste gases. Most of those gases are routed out of the engine, through the exhaust and then out the muffler. However, that can’t be done with 100% of the gases. Traces of oil and gasoline must be re-burned in order to reduce emissions and improve fuel economy. This is where your positive crankcase ventilation (PCV) valve comes in.

Your car’s PCV valve really only does one thing – it routes gases back into the intake manifold so they can be re-burned. The PCV valve is used constantly – it’s active anytime the engine is running. This means that it’s subjected to a great deal of wear and tear. However, time and use aren’t the primary enemy here. Dirty oil is. If you don’t have your oil changed regularly, sludge can build up. This will contaminate the PCV valve and clog it, forcing you to change it more frequently.

There is no specific lifespan for your car’s PCV valve. It lasts as long as it lasts. Regular maintenance will help provide a longer use life, while neglecting your regular oil changes will shorten it. Ideally, the PCV valve should be changed with every major scheduled service (30, 60, 90K, etc.). However, it’s possible that the valve will fail in between services.

Because of the importance of the PCV valve and the fact that if it fails, you won’t be able to pass emissions testing (and your engine won’t run properly), it’s vital that you know a few of the key signs and symptoms that indicate your valve is failing or has already stopped working. Watch for the following:

  • Check Engine light (if the valve fails while stuck open)
  • Rough engine operation
  • Hissing noise from under the hood
  • Whistling or whining from under the hood
  • Oil collecting on the engine air filter (some makes and models but not all)

If you suspect there’s a problem with your car’s PCV valve, a certified mechanic can help diagnose the issue, and replace the positive crankcase ventilation (PCV) valve if necessary.

This article originally appeared on YourMechanic.com as How Long Does a Positive Crankcase Ventilation (PCV) Valve Last? and was authored by Valerie Johnston.


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