What are the symptoms of too small valve clearance?
3 Answers
Symptoms of too small valve clearance: The valve components will expand due to heat, causing valve leakage and burning of the valve seat. For deformed or burned valve seats, they must be corrected by reaming and grinding, and cannot be repaired solely by lapping with the valve. Valve seats that cannot be repaired should be replaced with new ones. The repaired or replaced seat must be coaxial with the guide hole, with a coaxiality error of less than 0.03 mm. When the engine is running, the valve will expand due to the increase in temperature. If there is no clearance or too little clearance between the valve and its transmission components in the cold state, the thermal expansion of the valve and its transmission components in the hot state will inevitably cause the valve to not close tightly, resulting in air leakage during the compression and power strokes, thereby reducing power. In severe cases, it may even be difficult to start. To eliminate this phenomenon, a certain clearance is usually left between the valve and its transmission mechanism during cold assembly of the engine to compensate for the expansion of the valve after heating.
If the valve clearance is too small, the most obvious symptom I've noticed after driving for so many years is that the engine starts to sound like a drum, constantly making a rattling noise, especially when accelerating. It's quite annoying. The car's power also noticeably decreases, making it feel sluggish when climbing hills, not as responsive as before. As for fuel consumption, it definitely increases. Even under the same road conditions, the fuel gauge drops faster, costing me a lot more on gas each month. Worse yet, the engine tends to overheat. During long summer trips, the temperature warning light on the dashboard comes on, which is quite alarming. If left unfixed, over time it could damage the valves or pistons, leading to much bigger repair headaches. I remember one long trip where this issue forced me to stop and rest several times, wasting a lot of time. Actually, regular engine checks and valve clearance adjustments are simple—just take it to a professional auto shop. Don't wait until a major problem arises and regret it later.
Bro, the valve clearance is too small. I noticed the engine sound is really weird when driving, like a machine gun firing, especially at low RPM. In terms of power, the throttle response feels sluggish, and overtaking isn't as smooth as before, which is frustrating. Fuel consumption has also increased significantly—I calculated nearly 100 bucks more per month on gas, which is exhausting. The engine tends to overheat too; the hood gets really hot when parked, making me hesitant to use the AC much in summer. If left unchecked long-term, the valves might get damaged or something, and replacing parts could cost hundreds or even thousands. Prevention is key—listen carefully to the engine sound when starting the car, and get it fixed ASAP if anything seems off. There are plenty of repair shops around these days, and it only takes about half an hour to adjust, saving future headaches. Oh, and regular maintenance can extend the engine's lifespan, avoiding unnecessary expenses.
