A thumping sound in an automobile should not be ignored, as the sound is a sign of a problem. Delaying repairs may result in further damage, which could increase the costs of repair and make the car unsafe.
Wheels can become bent from striking objects, and tires can develop bulges from broken belts or wear. Both problems may cause a thumping noise. Thumping sounds caused by wheel and tire problems will typically increase in frequency at higher speeds, though the sound may not be heard at lower speeds. These problems can often be spotted by visual inspection.
Worn or broken struts or strut mounts can create a thumping noise, especially when the vehicle hits a bump in the roadway. To test struts, bounce the rear of the car by forcefully pushing down on it and letting go. After letting go, the car should settle back to its original position without bouncing or noise.
Loose trim pieces near or in the wheel well can flutter in the wind while a car is being driven. These trim pieces may create a thumping noise as they strike other objects. A car owner can check trim pieces for looseness to determine if that is the source of the noise.
