What are the causes of abnormal engine noises?
2 Answers
Causes of abnormal engine noises include: 1. Aging or loosening of engine mounts: Their function is to reduce vibration and cushion the engine during operation. Once the mounts age or loosen, the engine will shake, resulting in abnormal noises; 2. Engine misfire noise: Excessive wear of pistons and cylinder walls leads to the clearance between them exceeding normal tolerance ranges, causing the piston skirt to impact the cylinder wall during engine operation; 3. Overly rich air-fuel mixture: When the engine's air-fuel mixture is too rich, symptoms include difficulty starting, poor acceleration after starting, uneven engine operation, black smoke from the exhaust, reduced engine power, and increased fuel consumption. These issues are often related to carbon buildup and clogged filters.
With over 20 years of auto repair experience, I've found engine noises stem from various causes. Piston wear or cylinder knocking is most common, often due to insufficient lubrication; worn connecting rod bearings produce a rattling sound; improperly adjusted valve clearance leads to ticking; aged or loose belts squeal; rusted water pump or alternator bearings also cause noise; obvious metallic clanging indicates loose exhaust pipes. Never underestimate these sounds – untreated, they may lead to complete engine failure. I recommend checking fluids and belt conditions during every maintenance, and immediately visiting a professional shop upon hearing abnormal noises. Never risk driving – safety comes first!
