What Causes the Car Alternator Belt to Squeak?
2 Answers
Car alternator belt squeaking is caused by: 1. The engine belt slipping on the alternator, air conditioning compressor, or power steering pump; 2. Improper adjustment of the engine belt tensioner or insufficient tensioner spring force. The solutions are: 1. Adjust the tension of the engine belt tensioner; 2. Replace the engine belt. The car alternator is the main power source of the vehicle, functioning to supply power to all electrical devices and charge the battery while the engine is running normally. Car generators can be divided into DC generators and AC generators. Since AC generators outperform DC generators in many aspects, DC generators have been phased out.
After all these years of repairing cars, I've seen that alternator belt noise is quite common. It's mainly due to the belt aging and wearing out—over time it hardens, cracks, and starts squeaking. A belt that's too loose can slip and make noise, while one that's too tight increases friction noise. Additionally, rust on the pulley or dirt buildup can make the belt slide unevenly. During the rainy season, the belt gets wet and slippery, making noise more likely. When inspecting, first check the belt surface for cracks, then press it to test tension—it should give about 1 cm under normal pressure. Clean the pulleys thoroughly, and if the noise persists, you might need to replace the belt or adjust the tension. I've seen many cases where ignoring it led to the belt snapping, the alternator stopping, and the car losing power and breaking down on the road—how dangerous! So, early detection and action can save you from costly repairs later.
