What Causes Abnormal Engine Noises?

[DelHadley]

Severe abnormal noises in a car engine can be attributed to the following reasons: 1. Aging or Loose Engine Mounts: Engine mounts are rubber blocks placed between the engine and the frame to reduce vibrations and cushion the impact during engine operation, as well as to secure the engine in place. Once these mounts age or become loose, the engine may shake, resulting in abnormal noises. 2. Engine Misfire Noise: An engine misfire occurs when one or more cylinders fail to function properly. Common symptoms include intermittent exhaust flow, noticeable shaking of the exhaust pipe, and clear abnormal engine noises such as a "thumping" sound. 3. "Piston Slap" Noise: Due to poor lubrication or excessive wear between the piston and cylinder wall, the clearance between them exceeds the normal tolerance range. During engine operation, the piston skirt strikes the cylinder wall, producing a distinct "clanking" sound, which is usually more noticeable at idle or low speeds.