What Causes Abnormal Noise During Cold Engine Start?

[LeJuliana]

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.