What Causes the Metallic Knocking Sound in the Exhaust Pipe?
2 Answers
The metallic knocking sound in the exhaust pipe is caused by a lean air-fuel mixture. Here is an introduction to car exhaust pipes: 1. Definition: The car exhaust bellows, also known as the car exhaust flexible pipe, is installed in the exhaust pipe between the engine exhaust manifold and the muffler. It provides a flexible connection for the entire exhaust system, thereby reducing vibration and noise, facilitating installation, and extending the service life of the exhaust muffler system. 2. Material selection: Ferritic stainless steel has a small thermal expansion coefficient, high thermal conductivity, excellent resistance to high-temperature oxidation under repeated heating and cooling conditions, and good pitting corrosion resistance.
A while ago, my car's exhaust pipe kept making a metallic knocking sound, producing a constant clunking noise while driving, which was particularly annoying. After checking for a long time, I found that the most common issue is the exhaust pipe hangers being loose or rusted. Those small brackets wear out and loosen over time, causing the exhaust pipe to sway and hit the undercarriage when driving over bumps. Sometimes, when the car heats up and the metal expands and contracts, it also makes clanging noises. If left unfixed for too long, the entire exhaust pipe might fall off or corrode further, leading to exhaust leaks, which not only affects driving safety but also wastes fuel unnecessarily. I recommend going to a professional repair shop as soon as possible to check the hangers, brackets, and joints—replacing these parts doesn’t cost much and solves the problem. Also, pay attention to any unusual noises when warming up the car before driving to detect potential issues early.
