What Causes the Abnormal Noise When Starting a Mercedes-Benz?
2 Answers
Reasons for abnormal noise when starting a Mercedes-Benz: Engine Mount Rubber Aging or Loosening: The engine mount rubber is the rubber block placed between the engine and the vehicle frame. Its purpose is to reduce vibrations and absorb shocks during engine operation, as well as to secure the engine in place. Once the engine mount rubber ages or becomes loose, the engine may start to vibrate, and in severe cases, a "clicking" abnormal noise may occur. Overly Rich Air-Fuel Mixture: When the engine's air-fuel mixture is too rich, symptoms include difficulty accelerating after starting, uneven engine operation; black smoke from the exhaust pipe, accompanied by a "clicking" abnormal noise from the engine, sometimes with backfires; reduced engine power and increased fuel consumption. "Piston Slap" Abnormal Noise: Due to poor lubrication conditions, excessive wear of the piston and cylinder wall can cause the clearance between the piston and cylinder wall to exceed normal tolerance ranges. During engine operation, the piston skirt impacts the cylinder wall, producing a crisp "clicking" sound, which is usually more noticeable at idle or low speeds.
I had a similar issue with my Mercedes before. After taking it to the repair shop, they found it was a starter motor problem. The gears inside were severely worn due to the car's age, causing a clicking sound during startup. Another possibility is a loose belt, which produces a harsh squealing noise when slipping. It's also worth checking the exhaust pipe bracket – if the mounting bolts are loose, it can rattle during cold starts. The worst-case scenario would be internal engine issues, like a worn or stretched timing chain, which creates a metallic grinding noise. I recommend getting it diagnosed at a dealership as soon as possible. These noises are not just annoying; ignoring them could lead to a breakdown. Never overlook startup noises, especially in winter when they're more likely to occur.
