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Symptoms of a clogged PCV valve

What are the symptoms that are caused when a PCV valve gets clogged? Is it common to see oil leakage when the car is being driven?


  • edited January 2010
    Yes. If the PCV system is plugged it allows crankcase pressure to build inside the engine. This pressure seeks an alternative source of release and with it oil can be pushed out of the engine.


  • edited January 2010
    if you think it is bad, replace it. PCV valves are cheap and easy to install. might take all of 5 minutes to do.

    the question i have is where is the oil leaking from?
  • edited January 2010
    If the VALVE is plugged up, chances are the entire SYSTEM is plugged up and just replacing the valve will do little..The port that supplies the PCV with vacuum usually needs to be cleaned out too..Usually, when they are plugged up, the air intake plumbing will be full of oil-blow-back...
  • edited January 2010

    In addition to the other good information that you have been given, I want to add that a clogged PCV can contribute to sludging of the engine. If there is any doubt about the condition of the PCV valve, change it. When a part is this cheap, you should not hesitate.
  • edited January 2010
    yes. msay be time to buy some "motor flush" and change the oil, even if it isn't due just yet. I bet the intake ports a clogged up with carbon as well. a quick 'seafoam" treatment should help with that as well.
  • edited January 2010
    Thanks to everyone who replied! I know that the PVC valve is cheap and will certainly replace it. I was unable to spot the source of the leak. The car does not appear to leak when it is just sitting there parked as there are no oil spots on the ground. However, there is a burning smell when driving and the oil level drops so you know it is leaking while driving. I suspect that the oil that is leaking is hitting some hot surface such as an exhaust pipe or manifold surface. There isn't any oil mixed in with the coolant so I do not suspect a head problem. The car runs just fine from a performance standpoint.
  • edited January 2010
    I would suspect leaking valve cover gasket(s).
  • edited January 2010
    they make a special dye that you can add to the oil that flouresces under a black light. it really helps when trying to track down an oil leak.

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