What Causes the Squeaking Sound During Cold Start?
2 Answers
Reasons for squeaking sound during cold start: 1. Loose belt - when hearing the sound, you can wet the belt with water; if the sound disappears, it indicates the belt is loose; 2. Slippage caused by aging of water pump belt or engine belt leading to abnormal noise; 3. Lack of lubrication in components such as water pump impeller, water pump bearing or generator bearing has caused wear; 4. Possible failure of carbon brushes inside the starter motor. The working principle of starter motor is: after being powered, the electromagnet engages the starter motor's gear with the engine's flywheel, rotating simultaneously to drive engine startup, then the gear quickly retracts after engine starts.
I've experienced the squeaking noise during cold starts too many times. It's usually a belt issue—the alternator belt or A/C belt is more prone to making this sound in cold weather because rubber contracts and hardens, increasing friction. Once, I ignored a squeak in my car, and later the belt snapped, causing the alternator to fail—I almost got stranded on the road. That was a hard lesson. Worn water pump bearings can also cause similar noises, especially in winter when temperatures drop. I recommend owners listen for the source of the noise during startup and do a quick visual check for cracks or looseness in the belts. During regular maintenance, have a mechanic inspect and adjust the tension. Generally, belts should be replaced every 60,000 km—it's a low-cost fix that can save big money. Don't delay addressing it. Also, avoid aggressive acceleration and let the engine idle to warm up for a few minutes, which helps reduce noise and prevent failures. These small habits can make your vehicle more durable.
