What Causes Abnormal Noise During Cold Start?
2 Answers
There are several main reasons for abnormal noise during cold start: 1. Lack of lubrication in the starter internal gears: This causes the starter to become stiff or stuck, preventing the gears from retracting promptly. 2. Excessive dirt inside the starter or ineffective lubricant: When the flywheel forcibly drives the starter to rotate, the speed difference between them creates abnormal noise. 3. This noise typically disappears after the starter warms up with the engine, but severe cases may produce noise with every start. To eliminate this noise, the starter requires cleaning, maintenance, or replacement.
I've encountered the issue of abnormal noises during cold starts many times, and there are quite a few possible causes. The most common one is a loose or aged engine belt, which produces a particularly noticeable squealing sound; when it's cold, the belt contracts and tightens, causing more friction and noise during startup. Sometimes, worn bearings in the starter motor or a loose alternator can also produce a dull sound. Another factor is that when the engine is cold, the lubricating oil hasn't warmed up and flows poorly, leading to insufficient lubrication in components like hydraulic lifters or valve mechanisms, resulting in a ticking noise. My suggestion is to first listen carefully to locate the sound: if it's coming from the front, it's likely a belt issue, while noises from the rear may indicate problems with the starter or alternator. If the noise disappears after the engine warms up, it's usually not a big concern. However, if it happens frequently, don't ignore it—it could lead to a broken belt and leave you stranded. Regular maintenance is key, and replacing a belt doesn't cost much but ensures safety and reliability.
