reverse alternater belt squeal

[mazdamaniac]

so ive noticed every once in a while when i have my lights raio and heater on and ty to reverse i get the alternator belt squeal. Then ill turn them all off and backup without any noise then back on and go about my business. Its kinda annoying tho so i checked my belt and it seems to be the right tightness and in fine condition. What could i do to fix this? It seems to only happen when its cold or rainy.

[EUNOS 96]

the alternator has more of a load when all those things are on, so it will be a little bit more resistant to the friction of the belt/pulley. the rain is very significant because even the slightest bit of moisture can change the coefficient of friction greatly between the belt and pulley. its common physics, you described the answer to yourself in more or less words there. if its agonizing and horrible to the point of concern, maybe try to throw some belt dressing on it (comes in an aerosol can at any autoparts store) or closely inspect the underside of the belt for cracks or wear.

[mazdamaniac]

Ill try that. I know its nothing bad its just really annoying. Thanks tho

[miata5620]

Also in my experince the only belts that don't squeal are gates or OEM belts which I think are made by gates.

[darkgreyNA]

Is it for sure belt squeal? Mine was making a horrendous noise that turned out to be the water pump bearing screaming as the alternator load came up and leveled off..... changed the water pump and the noise went away...