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How to Test a PCV Valve Without Special Tools

Model: (Various brands) Various
Part: Valve

Video tutorial

Testing the PCV (Positive Crankcase Ventilation) valve is simple and does not require special tools. Start the engine and let it idle.

Remove the oil filler cap. To check if it is functioning correctly, use a piece of paper or cardboard: place it over the opening; if it is sucked in, the valve is working. Alternatively, use a glove or a plastic bag: inflate it and place it over the opening.

If it deflates, it indicates that there is a vacuum and the valve is active. Listen for any hissing sounds; a hiss may indicate a problem.

If the valve is faulty, clean or replace it. This procedure is valid for most engines.


Posted on 3 August 2026 by ScegliAuto


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