# Belt Noise diagnosis



## xamnil (Aug 2, 2013)

Hello,
I hear intermittent squealing noise that radiates from the right side under the hood. I've had this on and off for a year or so. It sounds exactly like a high-pitched saw for a period of 3-5 seconds and then goes away. It occurs once 7-15 minutes. This seems like standard belt noise, however in my case its a little hard to diagnose precisely.

Basically, the *noise mainly occurs when all three of the following factors are present*: 1) weather is hot 2) ac is on high 3) car is accelerating or decelerating at higher rpms- going 60/80 mph.
If it gets very hot, I may hear it when accelerating/decelerating at medium rpms. 


Visual inspection of the serpentine belts shows them to be in good shape, neither cracked nor dirty. 

However there is a small thin narrow belt - directly under the serpentine belts - that has some dirt and rust on and around it. I hear it might be a water pump issue as well.


Can anyone give me a pointer or two here?

Thanks,
Max


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## smj999smj (Jan 1, 2006)

It's tough to judge wear on belts these days as many of them are made with EDPM and they don't crack as much as belts did years ago. First thing to do is make sure the belts are not loose; you may just need a belt adjustment. However, if the belts are older than 3 years, it might make more sense to replace them than adjust them. If replacing them, stick with good quality belts. I recommend genuine Nissan belts or Bando brand, which is an OEM supplier of belts to Nissan. If the belts are in good shape and properly adjusted, but still make noise, it may not be the belts but one of the pulley bearings or a bearing in one of the drive accessories, like the alternator or A/C clutch. One test is to use a spray bottle and spray water on the belt. If the noise is coming from the belt, the noise will usually go away when you spray it with water. If the noise doesn't change at all with the water, it may very well be a bearing.


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