What causes a loud noise from the car's chassis?
2 Answers
Possible causes of abnormal noises from the car chassis are as follows: 1. Noises when starting the vehicle are generally related to suspension system faults, or may be caused by loose or damaged engine mounts. 2. Noises during steering may be due to issues with the steering system or suspension system. During turning, the vehicle's tilt causes deformation of the suspension system, which also participates in the movement. 3. Noises during driving on good road conditions may be caused by faults in the braking system components, such as loose or worn parts, out-of-round brake drums, or uneven brake discs. 4. Problems with the bearings connecting moving and static parts. If it's a bearing issue, the driver can identify it by applying slight brakes; if the noise remains unchanged during uniform motion with brakes applied, it indicates a bearing problem. 5. Noises during driving on poor road conditions are mostly related to suspension system issues, but may also be caused by loose braking system components.
My experience tells me that a loud bang from the chassis is no small matter—you need to be immediately alert. This often indicates a major issue with the suspension system, such as a sudden spring fracture or a completely failed shock absorber, which can snap under pressure on bumpy roads. It could also be that you didn’t notice while driving and the chassis scraped against a large rock or concrete curb, causing underbody impact that deforms the protective plate or even cracks the oil pan, leading to leaks. If the driveshaft loosens and detaches, it can spin wildly and slam against the chassis with a loud noise. I remember once hearing a similar sound on the highway—I immediately pulled over to check and found that the rear suspension link had broken. Thankfully, addressing it in time prevented a bigger accident. So, if this happens, slow down and pull over—don’t push through. Have a professional mechanic inspect the suspension, chassis components, and drivetrain to avoid safety hazards.
