What are the symptoms of valve leakage?
2 Answers
The symptoms of valve leakage are as follows: 1. Valve burning leads to a decrease in the sealing between the valve and valve seat; 2. Poor grinding of the valve sealing ring during maintenance; 3. The valve clearance is adjusted too small, resulting in incomplete valve closure; 4. Foreign objects getting stuck during valve installation into the valve seat, causing poor sealing; 5. Carbon deposits on the conical surface of the valve and valve seat; 6. Pitting, scratches, stains, burns, or dents on the valve working surface; 7. Excessive runout of the valve and valve stem; 8. Excessive coaxiality deviation between the valve guide hole and seat hole. More information about valve leakage is as follows: 1. The knocking sound caused by valve leakage is due to continuous knocking between the tail end of the valve stem and its driving component when the engine is idling. 2. The knocking sound increases with higher engine speed, but there is little change in the sound when the engine temperature changes or when the ignition is cut off.
Last time I got my car repaired, I encountered valve leakage issues. The car felt noticeably sluggish with no power, and even when I floored the accelerator while climbing a hill, the RPM wouldn't go up. Cold starts were particularly difficult—it took multiple attempts to fire up, and the exhaust pipe would puff out white smoke like popping firecrackers. The most annoying part was the rough idling that shook like sitting on a massage chair, vibrating the steering wheel. Engine oil consumption also increased, with exhaust emitting a pungent burnt smell, and even the check engine light came on. The mechanic used a cylinder compression tester and found the cylinder pressure was almost half of the normal value, confirming it was a valve sealing problem.
