What Causes the Rattling Noise When a Car Starts Moving?
3 Answers
Due to excessively low engine oil temperature and ambient temperature, abnormal noises occur when the car starts moving. Here are the detailed explanations: 1. When the engine oil temperature is too low, various components inside the engine lack lubrication, resulting in increased friction between parts, which leads to abnormal noises. This is a normal phenomenon; 2. Engine oil is referred to as the lifeblood of the engine. Inside the engine, it not only serves as a lubricant but also performs functions such as cleaning, sealing, cushioning, rust prevention, and heat dissipation. Without engine oil, the engine cannot operate normally.
I've encountered that clunking noise during startup several times! It's most likely an issue with the suspension system, such as worn-out ball joints or loose control arms in the front wheels. When the car starts slowly, these components bear the load and make that clunking sound, almost like they're protesting. The inspection method is simple: open the engine compartment to check for any loose parts in the chassis, or ask a friend to step on the accelerator while you listen for the source of the noise. If ignored, suspension failure could lead to unstable cornering, which is quite dangerous. It's best to perform regular maintenance, especially after driving on bumpy roads frequently, as these issues tend to arise more easily. After I got mine fixed, it only cost a small amount to restore quietness—safety first!
The rattling noise during startup is indeed annoying. I think it might be caused by a loose exhaust pipe or underbody cover. My own car had this issue before, especially during slow starts or turns when the noise was louder. Upon closer inspection, it turned out to be corrosion on the exhaust pipe mounting bracket. Components under the chassis are prone to rust due to accumulated water, which causes that rattling sound. Before driving, it's recommended to shake the exhaust pipe by hand to check for looseness. If the noise comes from the rear, nine times out of ten this is the problem. Fixing it isn't expensive, but leaving it unaddressed long-term may affect exhaust efficiency and prevent proper gas dispersion. Drying the chassis after car washes can help prevent rust.
