What Causes the Zizzing Sound After Starting the Vehicle?
2 Answers
The zizzing sound after starting the vehicle is caused by an issue with the engine belt. The engine belt is the main belt in a car, connecting components such as the generator, air conditioning compressor, power steering pump, idler pulley, tensioner pulley, and crankshaft pulley. Its power source is the crankshaft pulley, which drives the other components to operate together. When small cracks appear on the contact surface between the belt and the pulley, replacement is necessary. The engine is the device that provides power to the car, acting as the heart of the vehicle and determining its power, fuel efficiency, stability, and environmental performance. Depending on the power source, car engines can be categorized into diesel engines, gasoline engines, electric vehicle motors, and hybrid engines.
I've been driving for over a decade and have encountered many cases where vehicles make a squealing sound after starting. The most common issue is with the belt system. When the alternator belt, AC belt, or water pump belt becomes loose, it rubs against the pulley and creates a squeaking noise. A worn tensioner pulley bearing can also produce a rattling sound. These noises are usually more noticeable during cold starts because the rubber hardens at low temperatures, increasing friction. If the noise gets louder when accelerating, it's likely due to belt slippage. Ignoring this problem is very risky—if the belt snaps, the alternator stops working, the battery drains quickly, and all the lights and gauges go out, which is extremely dangerous. I recommend popping the hood immediately to listen for the source of the noise. If there's any unusual sound coming from the belt area, don't try to replace it yourself—take it to a professional mechanic for inspection. Minor issues like adjusting tension or lubrication might solve the problem, but if the bearing is damaged, it must be replaced. Regular maintenance, checking the belts every 50,000 to 100,000 kilometers, can prevent such issues. Safety first—don't skimp on this.
