What causes the abnormal noise when starting a Mercedes-Benz C260L?
4 Answers
Mercedes-Benz C260L starting with abnormal noise may be caused by parts noise or prolonged use of transmission fluid. Parts noise: The car's gear shifting structure consists of the gear lever, cables, gear selection and shifting mechanisms, shift forks, and synchronizers. The noise from these parts is relatively small. Prolonged use of transmission fluid: Prolonged use of transmission fluid can lead to sludge formation, increasing the wear of friction plates and other components. Wear in these parts can cause malfunctions resulting in noise. If the sound during gear shifting is relatively small and comes from near the gear lever, it is normal noise from the gear shifting mechanism. If the gear shifting produces a clicking sound, it is caused by a fault in the transmission gear impact.
I've been driving a Mercedes for seven or eight years, and it's quite common for the C260L to make strange noises when starting. Last time my car made a creaking sound from the chassis at low-speed starts, I initially suspected it was the brake pads, but upon lifting it, it turned out to be aging and cracked bushings on the lower control arm. Replacing this on a Mercedes isn't cheap—the dealership quoted nearly four thousand. Additionally, worn universal joints on the driveshaft can cause a clicking sound during starts, especially more noticeable when turning. A friend also encountered insufficient differential oil or worn CV joints. I recommend finding a reliable repair shop to lift the car and inspect it. Don't delay repairs, as issues with these chassis components can affect handling and safety. Finally, check the torque on the tire bolts—it's the simplest thing but easily overlooked.
I know all about Mercedes-Benz rattles. If you hear a clunking noise from the chassis when starting the C260L, nine times out of ten it's a suspension issue. The stabilizer bar bushings are the most prone to failure - rubber components tend to deform after three or four years. Last month when helping my cousin check his car, we found the noise was caused by seized front shock absorber upper mount bearings. Also, if the brake disc anti-rust coating isn't worn off properly, it can make a screeching sound during initial movement that disappears after a few kilometers. Worn transmission mounts are another hidden issue, especially noticeable during cold starts. Remember to distinguish between different noise types: metallic clanging and rubber friction sounds require completely different solutions. I recommend recording a video of the sound for your mechanic - it can save significant diagnostic time.
I just resolved the rattling issue with my C260L. The dealership inspection found that the engine guard screws were loose, causing a buzzing resonance from the oil pan during acceleration. The technician said this is a common issue with German cars, especially in winter when rubber components harden. Also, if the brake disc protective wax isn't fully cleaned, the first few accelerations may produce sharp scraping sounds. Additionally, check the exhaust pipe hangers - when these rubber parts age, the exhaust system can shift and rub against the chassis. The recommended diagnostic process is: in parked position with brake depressed and in D gear, listen for the noise location; then gently accelerate to 10km/h, focusing on whether the sound is continuous or intermittent. Don't attempt DIY part removal - damaging Mercedes clips would create bigger problems.
