What Causes Abnormal Noises in the Engine Compartment?

[Roy]

Engine compartment abnormal noises may be caused by the following reasons: Abnormal noises in the engine compartment while driving could be due to issues like engine valve noise, piston noise, accessory noise, or even transmission noise and chassis noise. Since there are many potential causes of abnormal noises, an accurate diagnosis cannot be made without inspecting the actual vehicle. Additional Information: Sometimes, abnormal noises are heard from the engine while driving, but when the car is stopped for inspection, the noise does not occur even when the engine is running at the same RPM as when the noise was heard. In such cases, you can loosen the carburetor adjustment screw slightly and then restart the engine to see if the noise reappears, which can help identify its characteristics. If the noise still does not occur, you can try cutting off the fuel supply to a specific cylinder and performing a rapid acceleration test. This may help the noise to reappear and also determine the relationship between the noise and the specific cylinder.