What is the reason for the belt slipping sound when accelerating?
3 Answers
The reason for the belt slipping sound when accelerating is: severe belt wear. When the car's belt is severely worn, the contact area between the belt and the pulley will be significantly reduced. As long as the belt is pressed hard, the belt will sink deeply into the groove of the pulley. When the belt rotates, it becomes very difficult and produces a slipping noise. Generally, there are three main reasons for belt noise: 1. Aging of the drive belt: The drive belt is mainly made of rubber, and rubber will age after prolonged use, becoming harder and more brittle. The friction coefficient will also decrease, which will affect power transmission, leading to slipping and noise. 2. Insufficient belt tension: When the belt tension is insufficient, the belt is prone to slipping just like when it is aged. Belts are automatically adjusted for tightness through a large spring design that presses the belt, thereby regulating the belt's tightness. When the belt is too loose, the friction will also decrease, causing noise due to slipping. 3. Severe belt wear: When the car's belt is severely worn, the contact area between the belt and the pulley will be significantly reduced. As long as the belt is pressed hard, the belt will sink deeply into the groove of the pulley. When the belt rotates, it becomes very difficult and produces noise.
I've been driving for years, and my old car used to squeak when accelerating, which was the sound of the belt slipping. The issue usually lies with the accessory belt in the engine compartment being loose or worn out. When you step on the gas and the RPM increases, the belt's load increases, making it prone to slipping and creating noise. Causes include belt elongation leading to insufficient tension, the surface becoming smooth and slippery, the tensioner pulley getting stuck, or oil leaks contaminating the belt. This is common with belts like the alternator belt or the air conditioning compressor belt. It's recommended to open the engine hood and check for cracks or deformations in the belt. Don't delay; ignoring it could lead to belt breakage, causing the car to overheat and break down. Checking the belt condition every two years during maintenance is the most reliable approach.
I'm quite used to doing my own car repairs. The belt squealing is most noticeable during acceleration, mostly caused by a loose or worn-out belt slipping. You can DIY the inspection: first, turn off the engine and open the hood, press the middle of the belt with your hand—it should have about half an inch of give. If it's too loose, grab a wrench to adjust the tension screw. Check for any cracks or grease on the belt. Replacing it with a new one isn’t hard, and buying the right model won’t cost more than a few bucks. Avoid using lubricant sprays—they’ll only make things worse. Stay safe by wearing gloves to prevent burns. While driving, minimize sudden aggressive acceleration to protect the belt and extend its lifespan.
