What causes the clunking sound while the car is moving?
4 Answers
During driving, the engine may experience significant vibrations, and even when in neutral with the brake pressed, vibrations persist, especially noticeable during cold starts when the entire vehicle shakes. Body vibrations are essentially a warning signal, potentially indicating deformed wheel rims or unstable engine idle speed. Ignoring these signs could lead to major malfunctions. 1. Causes of vibrations during cold starts: Typically in colder weather, the absence of idle speed in cold conditions makes vibrations normal. However, if severe vibrations persist after the engine warms up and returns to normal RPM, it's advisable to check for a dirty throttle body. Maintenance and cleaning of the fuel system, throttle body, and air filter are recommended. 2. Causes of vibrations during acceleration: Acceleration-induced vibrations can cause the front of the vehicle to sway side to side. Therefore, the first step is to inspect whether the left and right half-shafts are bent and examine the inner walls of the left and right inner CV joints for wear and indentations, as these issues are often caused by damaged inner CV joints. 3. Causes of vibrations during gear shifting: Apart from improper clutch and throttle coordination, vibrations during gear shifting might stem from the vehicle itself, such as aging clutch discs, pressure plates, pilot bearings, or input shaft bearings. Hence, it's crucial to inspect these components. If these parts are indeed the issue, they could accelerate wear on transmission components, reduce their service life, and increase fuel consumption.
My car had a similar clunking noise before, especially noticeable when driving above 70 km/h. After inspection, I found out it was an issue with the chassis suspension system—possibly the shock absorbers aging and leaking oil, or the ball joints of the suspension links becoming loose. These parts can develop metal fatigue over time, leading to clunking sounds. Worn wheel hub bearings can also produce rhythmic clunking noises, especially louder when turning. Additionally, it's not uncommon for the exhaust pipe's rubber hanger brackets to come loose, causing the metal pipe to hit the chassis on bumpy roads, creating this noise. I recommend you first pay attention to when the noise occurs: if it happens when going over speed bumps, it's likely a suspension issue; if it's during steady-speed driving, it could be the wheel hub bearings; if it's particularly loud during cold starts, check the exhaust pipe. Get it inspected at a repair shop as soon as possible—don't delay, as these minor issues can worsen and affect steering control.
A clunking noise while driving can be quite annoying, and it's essential to check several key components. Start with the tire system—excessive tire pressure or deformed rims can cause the tires to bounce and hit the wheel arches, producing a metallic knocking sound. The braking system shouldn't be overlooked either; loose calipers or brake pads worn to the limit can also create similar noises. Another common culprit is worn universal joints on the driveshaft, especially noticeable in rear-wheel-drive cars during acceleration. If the engine mounts are aged, engine movement hitting the frame can also result in clunking. You can perform a simple check: lightly apply the brakes on a safe stretch of road—if the noise disappears, it's likely a brake issue. If the sound changes significantly during turns, it might indicate a drivetrain problem. Faults in these components can affect driving stability, so early repairs are crucial for peace of mind.
Don't panic when hearing clunking noises while driving - it's often loose mechanical components. Last week I helped a neighbor diagnose a similar issue and found the mid-pipe exhaust hanger bracket had broken, causing the pipe to hang and hit the undercarriage. Worn wheel bearings can also produce rhythmic metallic knocking that intensifies with speed. Also check the underbody panels - many cars' plastic shield screws loosen and create drum-like banging sounds. Immediately reduce speed and visit a repair shop for lift inspection. If accompanied by steering wheel vibration or body floatiness, it may signal impending wheel hub bearing failure - in such cases you must stop immediately and call a tow truck.
