Reasons for Poor Valve Sealing
2 Answers
Possible causes include severe carbon buildup on the valves, abnormal wear of the valve seat rings, and mechanical failures in the valve assembly. Below are the related reasons for mechanical failures in the valve assembly: 1. Carbon deposits can be considered the "number one enemy" of the engine, appearing almost everywhere, and the valves are no exception. When carbon deposits on the valves are severe, they may cause the valves to not close tightly. The root cause of valve carbon buildup is poor engine combustion, which can be due to various factors such as oil issues, prolonged poor working conditions of the vehicle (road conditions, driving habits, etc.), or engine system failures. 2. During engine operation, the valves and valve seat rings continuously undergo high-speed impacts and friction, making wear inevitable. However, if there is abnormal wear, it can lead to premature failure of mechanical components, resulting in poor valve sealing.
From my experience in car repair, the most common reason for valves not sealing properly is excessive carbon buildup. Especially when using low-quality gasoline, carbon deposits get stuck between the valve and valve seat, compromising the seal. Additionally, valve spring fatigue or breakage reduces tension, preventing the valve from being fully pressed shut; a bent valve stem is prone to deformation during high-speed driving or engine overheating; wear and aging of the valve seat over time lead to increased gaps due to metal fatigue; and issues with hydraulic lifters, such as insufficient or dirty oil, can cause lifter failure. These problems may range from causing compression leaks, power loss, and increased fuel consumption to severe cylinder damage. It's recommended to regularly clean the throttle body, use high-quality oil, avoid prolonged high-speed engine operation, and listen for unusual noises at idle to make a simple assessment.
