What are the sounds of engine knocking?
2 Answers
Engine knocking sound is a crisp and rhythmic metal knocking noise that varies with temperature changes. The causes of engine knocking include: 1. Bent or twisted engine connecting rod; 2. Excessive carbon deposits in the engine; 3. Poor engine lubrication conditions; 4. High cylinder pressure at high speeds. Solutions for engine knocking: 1. If the knocking sound disappears after the car starts and the temperature rises, you can continue driving; 2. If the knocking sound persists and becomes more noticeable after the engine reaches normal temperature, the owner should stop and inspect promptly to prevent traffic accidents; 3. After removing the cylinder head and extracting the piston, if severe cylinder ovality, scoring, or excessive clearance between piston and cylinder is found, replacement is necessary - replace cylinder liner, piston, and piston rings; 4. If connecting rod deformation is found, replacement should be performed whenever possible.
That sound you're asking about is all too familiar to me! My own old ride had the exact same issue last year. When accelerating, you could hear a 'clack-clack-clack' metal knocking noise coming from the engine bay, like hitting an empty oil drum with an iron rod. It was especially noticeable when climbing hills or stomping on the gas pedal. The mechanic told me it was classic piston pin wear—the clearance between the connecting rod small end and piston pin had become excessive. He warned that if not fixed promptly, it could eventually score the entire cylinder wall. So when you hear this rhythmic metal knocking, shutting off the engine for inspection is absolutely the right move. By the way, this sound is often confused with timing chain noise, but chain noise is more fragmented and most noticeable during cold starts.
