What sound does a loose timing chain make?

[Sanchez]

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.

[MacSkylar]

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.

[EmiliaMarie]

As a technician who deals with various engine failures daily, I'm most familiar with the acoustic characteristics of a loose timing chain. The typical manifestation is a continuous 'rustling' sound mixed with metallic clinking at idle, which turns into a high-frequency 'ticking' sound when the RPM exceeds 2000. This is completely different from the single knocking sound caused by excessive valve clearance, accompanied by slight engine vibration. The issue often stems from aging or failure of the hydraulic tensioner's sealing ring, or damage to the chain guide. Neglecting it may lead to timing deviation, potentially causing pistons to directly hit the valves, necessitating engine removal for repair.

[SanLane]

Veteran drivers remind you to pay attention to this sound: When starting the car in the morning, the engine makes a dry 'clicking' noise, like an amplified version of a bicycle chain slipping. After the engine warms up, it turns into a continuous, fine metallic friction sound, which is quite annoying. This indicates that the chain elongation has exceeded its limit, as the lifespan of the original chain is often affected by oil quality. I've seen a neighbor's car dragged until the chain skipped, and starting it directly bent the valves, costing over six thousand to repair the engine. Now, whenever I hear abnormal chain drive noises, I habitually check the oil level.

[VanPenelope]

During the last maintenance, I recorded the abnormal noise from the chain: at idle, there was a distinct metallic scraping sound, similar to a 'zira zira' sound of scraping against sheet metal. The technician said this was the sound of the chain swinging sideways and hitting the guide rail, caused by insufficient tensioner pressure. At high speeds, the frequency of the noise increases with RPM, but the tone becomes more muffled. It's recommended to also check if the engine warning light is on, as excessive chain slack can trigger the timing sensor alarm. When replacing, it's best to change the guide rail together, as adjusting the tensioner alone only provides a temporary fix.