What Causes the Exhaust Pipe Rattle in BMW 5 Series?
2 Answers
BMW 5 Series exhaust pipe rattle is caused by excessive carbon buildup in the intake tract. Reasons for excessive carbon buildup in the intake tract: Due to excessive carbon deposits and dirt in the intake tract, the cross-sectional area of the air passage changes, making it impossible for the control unit to precisely regulate idle air intake. This results in either too rich or too lean air-fuel mixture, causing abnormal combustion or engine vibration after startup, and in severe cases, failure to start. Hazards of exhaust pipe rattle in vehicles: Regardless of the cause, exhaust pipe rattle indicates an abnormality in the vehicle. If the exhaust pipe is damaged, it not only causes noise pollution but also significantly impacts the ecological environment if exhaust gases are released without being purified by the catalytic converter. In cases of engine misfire, it not only greatly affects the normal operation of the engine but also leads to severe environmental pollution due to incomplete combustion of exhaust gases.
Last time I drove a BMW 5 Series, I also encountered exhaust pipe noise that sounded like metal knocking. After checking for a long time, I found out it was due to aged exhaust pipe hangers. These rubber parts become hard and crack over time, causing the exhaust pipe to rattle when the car goes over bumps. Another time, it was the gasket at the connection between the exhaust pipe and the engine that was burnt and leaking, making a puffing sound like air escaping. Cars with modified exhaust systems need to pay extra attention to the welding points. A friend's car had a cracked weld at the tail section, causing resonance and noise in the exhaust. Now, I check the condition of the hangers under the car every six months. Rubber parts should be replaced every five or six years. If you hear abnormal noise accompanied by a drop in power, it might be that the ceramic substrate in the catalytic converter is broken, and you should get it fixed immediately.
