What are the symptoms of excessive valve clearance?

1 Answers
MariaLee
07/29/25 10:57am
The symptoms of excessive valve clearance are: 1. Insufficient engine intake and incomplete exhaust, leading to a decrease in engine power; 2. Impact noise between components of the valve train, accelerating wear; 3. A continuous crisp tapping sound. The larger the valve clearance, the lower the combustion chamber pressure, resulting in poorer power and louder engine noise. When the engine is running, the valves expand due to temperature rise. If there is no clearance or the clearance is too small between the valves and their transmission components in the cold state, the thermal expansion of the valves and their transmission components in the hot state will inevitably cause the valves to close improperly. This results in air leakage during the compression and power strokes, reducing power output. In severe cases, it may even make the engine difficult to start.
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