How to Check if the PCV Valve is Good or Bad?

3 Answers
MacJustin
07/28/25 9:25am
PCV Valve inspection methods are as follows: 1. Keep the engine idling, remove the PCV valve from the cylinder head cover hose, then check if the PCV valve is clogged. Place your hand on the PCV valve interface, and you should feel a strong vacuum suction with your fingers; 2. After reinstalling the PCV valve, remove the crankcase intake pipe from the air filter, then cover the pipe opening with a thin piece of paper. As the pressure in the crankcase decreases, the paper should be noticeably sucked towards the pipe opening. After the engine stops running, remove the PCV valve and shake it by hand to check. If you hear a clicking sound, it indicates that the PCV valve is flexible and usable.
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DiHaven
08/11/25 3:41pm
I enjoy DIY car repairs, and checking the PCV valve is straightforward: First, turn off the engine and let it cool. Then locate the PCV valve, usually near the valve cover or intake pipe. Disconnect the hose and remove the valve directly. Shake the valve and listen for sounds: If you hear a small metal ball rattling inside, the valve is good and functioning properly. If there’s no sound at all, it might be clogged or broken. Also, inspect the hose for cracks or oil buildup, as these details can affect sealing. I once had abnormal fuel consumption and tried this—performance improved after cleaning. By the way, a faulty PCV valve can also cause engine misfires or blue smoke. Checking it every 10,000 km can save you a lot on repairs. Remember to work in a safe environment and avoid wearing gloves to prevent static electricity.
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DiHarley
09/28/25 3:53am
I've been driving an old car for years, and checking the PCV valve is all about preventing issues: Start the engine and let it idle, gently remove the valve's hose, and place your hand near the valve opening to feel for vacuum suction. If you feel strong suction, the valve is fine; if the suction is weak or absent, the valve might be clogged. A good PCV valve makes a light, crisp sound when shaken, while a bad one, clogged with sludge, remains silent. Also, check if the oil is contaminated—excessive oil grime in the engine bay could indicate valve exhaust leaks. Make it a habit to inspect the valve during every oil change for easy engine maintenance, extended lifespan, and avoiding costly overhauls.
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