What Causes the Abnormal Noises in BMW 3 Series?

[Freya]

The causes of abnormal noises in the BMW 3 Series need to be determined based on the source of the noise. The specific analysis is as follows: Body Noises: This issue is usually caused by insufficient body rigidity, leading to deformation during driving, resulting in friction or shaking between the doors and the frame, or friction between steel plates due to loose welds. Applying adhesive strips on the doors and windows or placing rubber pads in the friction areas may help reduce or eliminate the noise. Some cars have significant wind noise, which is related to their design. Additionally, loose fastening of body components can also cause abnormal noises, which can generally be resolved by tightening the screws. Engine Compartment Noises: There are various possibilities for noises originating here. A high-pitched belt squeal is usually caused by belt slippage. If there is a dry metal friction sound when the engine is running, it often indicates damage to the bearings of the generator, water pump, or power steering pump. A hissing sound during engine operation may suggest a blockage in the exhaust system or a leak or break in the vacuum tube. It is important to note that if the noise comes from inside the engine, the owner is often unable to resolve it and should seek professional repair services.