What sound does a loose timing chain make?
2 Answers
A loose timing chain will produce a metallic friction sound. 1. Main causes of timing chain noise: Generally include lack of tension in the chain tensioner, elongation of the timing chain, abnormal wear of the guide chain plate, abnormal timing sprocket, etc., which involve replacement of mechanical parts. 2. Main function of engine timing belt: To drive the engine's valve train, enabling the engine's intake and exhaust valves to open or close at the appropriate time to ensure normal air intake and exhaust in the engine cylinders. 3. Precautions: The timing belt is recommended to be replaced every 60,000-80,000 kilometers, while the timing chain generally does not need replacement unless there is abnormal noise. The timing chain is not considered a wear part, but its operation relies entirely on engine oil for lubrication, so it is essential to change the oil regularly and avoid using inferior quality oil.
I just encountered a loose chain issue last month. During cold starts, I clearly heard a 'clanking' metal friction sound coming from the engine bay, like two gears grinding against each other. After the engine warmed up, the sound changed to a rhythmic 'tapping' noise, especially louder when accelerating. Later, the mechanic said it was caused by chain elongation leading to tensioner failure, and the metal guides were worn with grooves. It needs immediate repair, otherwise, skipped teeth could damage the valve lifters, and the repair cost could exceed ten thousand. It's advised to stop driving and check the fault codes immediately when hearing such continuous metal abnormal noises.
