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Frequently asked questions about cars and motorcycles

If the car runs on three cylinders, it may be a valve sealing issue

Model: (Various brands) Various
Part: Valve

This video demonstrates a method to check valve sealing if you need to verify whether one of the cylinders is not performing properly. The YouTuber is pouring petrol into the combustion chambers. Before removing the cylinder head, compression was measured, and one of the cylinders was lacking. The method involves allowing the liquid to drop; the cylinder where the liquid descends has the lowest compression and sealing. A quicker method involves blowing into all the ducts, revealing that the first cylinder indeed has poor valve sealing on the head. Therefore, especially when hot, you will experience misfires; the only remedy is to recondition with reinforced valve seats, and the fault will disappear.

Updated on 1 September 2026 by ScegliAuto

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