What Causes Abnormal Noise in a Car Alternator?
3 Answers
Car alternator abnormal noise causes are as follows: Loose alternator belt: When the belt is loose, there will be relative movement between the belt and pulley, which produces a distinctive squealing noise. This mostly 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 during startup, spraying a small amount of water on the alternator pulley can help diagnose - if the noise disappears, it confirms the belt as the source. Worn or insufficiently lubricated bearings: This manifests as metallic grinding or continuous swishing sounds. After loosening the belt, manually rotate the alternator pulley to check for looseness or abnormal sounds. If confirmed as alternator issues, replacement or repair of the alternator is necessary.
When I notice abnormal noises from the car alternator, the primary suspect is bearing wear, as prolonged rotation causes bearing aging, resulting in sharp friction sounds or metal scraping noises. If the belt is loose or cracked, it may also produce squeaky noises, especially in cold weather or during engine acceleration. Loose internal components like coils or an unbalanced rotor can cause humming or rattling sounds. The inspection is simple: listen closely to the source of the noise while the engine is running, check if the belt is loose by pressing it to see if it's severely deformed. Ignoring it may lead to alternator burnout, battery discharge, and the car stalling on the roadside, which is very dangerous. I recommend visiting a repair shop as soon as possible for professional tool diagnostics. Regular maintenance, including checking belt tension and cleaning dust around the alternator, can prevent most issues, saving money and ensuring safety.
Last time I was driving, I encountered the annoying issue of the alternator making noise, sounding like a mouse squeaking. I thought it was a belt problem. I stopped the car to check and found that the alternator bearing seemed worn because there was abnormal vibration when it rotated. The belt was a bit loose, so I tried tightening the screws with a wrench, and the noise reduced. For internal issues, it's more professional and might require disassembly for inspection. Don't delay addressing this abnormal noise, otherwise the battery won't charge, and the car won't start, which would be embarrassing on the road. I also recommend recording the sound for the mechanic's reference. Pay attention to the alternator's condition regularly, such as cleaning to avoid dust buildup. Developing a habit of checking can prevent major repairs.
