What Causes Abnormal Noise During Cold Engine Start?
3 Answers
The reason for abnormal noise during cold engine start is that the internal gears of the starter lose lubrication, causing stiffness and jamming, which affects the timely return of the gears. Extended relevant information is as follows: 1. When there is abnormal noise during cold start, the car should be parked for a day, as the engine's lubricating oil has basically all flowed back into the oil pan. During a cold engine start, the oil pump cannot immediately establish oil pressure, preventing the formation of an oil film between components. After the engine runs for a while, oil pressure is established, an oil film forms, and the oil temperature rises. The "clicking" sound disappears once the engine operates normally. 2. Due to excessive dirt inside the starter and the failure of the lubricating oil, the flywheel engine forcibly drives the starter to operate at its own speed. Since there is a speed difference between the two, this causes the starter to produce the "grinding" sound that is heard. This noise only ends when the starter reaches the same thermal state as the engine, but in severe cases, the noise occurs every time the engine is started.
I think it's quite common for cars to make strange noises when starting cold. With over 20 years of driving experience, I've encountered this issue frequently. The problem usually lies with the belt - when it's cold, the belt becomes stiff or loose, causing constant squealing during startup. Sometimes it's due to low oil viscosity, resulting in insufficient engine lubrication and causing knocking sounds. My own car once had a broken exhaust pipe hanger, making rattling noises upon every start, which took several days to fix. I recommend checking the belt tensioner or pulleys, and adjusting them promptly if loose, otherwise it may accelerate wear or even break. Change to appropriate oil before winter to avoid insufficient lubrication. If the abnormal noise persists, visit a professional shop immediately to inspect the engine internals before minor issues escalate. Remember to warm up the engine for a few minutes during routine maintenance before driving to reduce impact.
My car squeals every time it starts cold. After asking around, it's most likely due to aging or loose belts. In cold weather, rubber hardens and causes more friction, making the sound very sharp. It could be an issue with the fan belt or the AC belt, and the noise worsens when the fan is turned on. Sometimes, it's due to excessive engine bearing or valve clearance, or insufficient lubrication. I've tried cleaning dirt off the belts and applying special lubricant to alleviate the problem. But if the sound turns into a metallic clanking, it might indicate low engine oil or an exhaust pipe leak—requiring immediate oil replacement or tightening screws. During regular maintenance, check for belt cracks to avoid sudden failures. Ignoring it can easily damage the engine, costing more and posing risks. It's recommended for beginners to schedule regular maintenance.
