What Causes Abnormal Noise from a Car Alternator?
2 Answers
Abnormal noise from a car alternator can be caused by the following reasons: 1. Loose alternator belt: When the belt is loose, there will be relative movement between the belt and the pulley, producing a distinctive squealing noise. This often occurs when starting the vehicle or using high-load electrical devices like headlights, accompanied by a burning rubber smell in the engine compartment. If abnormal noise occurs when starting the vehicle, spraying a small amount of water on the alternator pulley can help diagnose the issue - if the noise disappears, it confirms the belt as the source. 2. Worn or insufficiently lubricated bearings: This produces a metal grinding noise or continuous brushing sound. By loosening the belt and manually rotating the alternator pulley, you can check for looseness or abnormal sounds. If the problem lies with the alternator, replacement or repair of the alternator is necessary.
The issue of abnormal noise from the alternator is quite common. Usually, it's due to bearing wear—those small ball bearings can start squeaking when they're worn out. Belt problems are another culprit; if the belt has cracks or is loose, it can produce a flapping sound during operation. Loose installation is also a factor—if the alternator's mounting bolts are loose, it can create a humming noise. Don't underestimate these issues. Over time, they can lead to unstable power generation, preventing the battery from charging properly and even causing the car to fail to start. In severe cases, it might damage other electronic components. I've encountered this several times—getting it checked early at a repair shop and replacing a small part can save time and money. During routine maintenance, checking the belt tension can effectively prevent abnormal noise. Don't wait until the problem worsens.
