This may date me but so what? Lots of explanations about what can cause belts to squeal or slip but with serpantine belts and auto torque adjusters, the problem isn't as common as it used to be.
Thanks for the confirmation.. (I said Serpantine belts were better for eliminating squeals way up the page) Nice to know I got it right
I do agree with the majority here though,,, Tension adjustment or belt wear are the likely culprits
Here is one that was ask of Click and Clack, the car talk guys.... They got it wrong, sort of (I do admit thier fix would cure it)
Drive car all day, stop and go, no problems... Drive it after dark and it won't re-start in the morning
They suggested a new alternator
My cure: Re-tension the fan belts (the car I had that did this (2 of them) and the 3 others (Belonging to others I met, 2 on the road, on e in a store) all had "V" belts, not serp belts, and in each case belt tension was off
In one case the car had the WRONG SIZE belt, I had to get a wider belt (the size it had was the size specified in the manual, the pullies were not the ones specified in the manual though) that was a FORD