What causes the screeching sound at the moment of engine startup?
3 Answers
The screeching sound at the moment of engine startup is caused by the lack of lubrication in the starter's internal gears, which affects their timely retraction. Causes: When starting the engine, the starter motor rotates to drive the flywheel, thereby starting the engine. At this point, the engine's speed is driven by the starter, so the engine speed is lower than the starter speed. When the engine starts and its speed exceeds the starter speed, manually operating the ignition switch cuts off the power supply, shutting down the starter. Due to internal dirt in the starter and ineffective lubrication, the flywheel engine forcibly drives the starter to operate at its own speed. Because there is a speed difference between the two, this causes the starter to produce noise. Methods to eliminate the noise: The noise will only stop when the starter reaches a hot state along with the engine, but in severe cases, the noise occurs every time the engine is started. To remove this noise, simply clean and maintain the starter or replace the starter.
My old car used to make a screeching sound when starting, like something was scraping, which was quite alarming. That time before a long trip, I neglected to check it, and ended up stranded on the road when it wouldn't start. After towing it to the repair shop, they found the starter motor's gear was worn out and couldn't engage properly. Other common causes include loose belts or an aging battery causing unstable current. I think if you hear this sound, don't delay—get it checked at a repair shop as soon as possible. Especially in cold winter weather, parts are more prone to stiffening, making the noise even more noticeable. Ignoring it could lead to a breakdown on the road, and repairs would be more expensive. Replacing the starter motor can solve the issue, so pay more attention to the starting system during regular maintenance to avoid unnecessary expenses.
If the engine makes a screeching sound at startup, I would first open the hood to locate the source of the noise. It could be caused by a loose or worn drive belt slipping, or the starter motor components needing lubrication. I usually check if the battery terminals are loose and if the voltage is sufficient, then try tightening the belt with simple tools like a wrench. If the noise persists, the flywheel ring gear might be damaged and need replacement. DIY car repairs save money and are practical—I recommend learning some basic knowledge, such as regularly cleaning the engine bay to prevent corrosion, which can help avoid issues. But always prioritize safety and avoid touching components recklessly; seeking professional advice is more reliable. Don’t overlook these maintenance details—they extend part lifespan and save hassle.
