What are the methods to determine abnormal noise from engine belts?
2 Answers
Methods to determine abnormal noise from engine belts: You can identify which belt is causing the issue by listening to the sound. If the noise occurs when the air conditioning is turned on, it might be the air conditioning compressor belt. If the noise appears during a cold start, it could be the engine belt, and you can check them one by one. If there are multiple belts in the car and you can't pinpoint which one is problematic, you can start the car and pour a little water on the belts. If the noise disappears, it indicates that the specific belt is the issue, and you can then check whether it's loose or of poor quality. Pouring water on the engine belt to stop the noise increases its stickiness temporarily, but the belt will return to its original state once the water dries.
I've been repairing cars for many years, and the method to identify engine belt noise is actually quite practical. After opening the engine hood and starting the car, listen carefully for any sharp squealing or harsh noises, which are usually most noticeable during cold starts or acceleration. Next, inspect the belt surface: if you see cracks, edge damage, or signs of glazing, it indicates severe wear. You can perform a tension test: press your finger on the middle of the belt—it should normally depress about half an inch; if it's too loose or too tight, it needs checking. The water spray test is even more direct: while the engine is running, lightly spray some water on the belt. If the noise suddenly disappears, it means belt slippage is the main cause. Don’t underestimate these steps—ignoring belt noise can lead to sudden breakage, leaving you stranded, especially dangerous at high speeds. I recommend checking the belt condition during every maintenance session or having a technician take a quick look during oil changes—it can save you a lot on repair costs.
