Chevrolet Repair: squeeky belts, 2000 mazda 626, mazda 626

Question
I just had my belts replaced in my 2000 Mazda 626 (I understand you work with Chevy's, however, I expect that the problem may be addressed similarly). My old belts were barely making noise and I had them replaced(they were 4 years old and somewhat cracked).
However, when I got my car back, the new belts were squeeling loudly, so I took the car back. It was okay the first few times I drove it, but now it is screaming again upon start-up.
Should I suspect my mechanic installed them incorrectly or is it more likely to be the fault of the new belt (or worse, costly mechanical malfunction)?
Thank you Mark :)

Answer
Hello Carol, Well if the belt was ok before they installed a new then I would say that either they installed it the wrong way(routing) or the belt is too long (wrong belt). On most cars they have a belt tensioner which has a spring inside it to keep the belt tight. It the belt is to long, the travel of the tensioner won't be enough to keep the belt tight and then it will make noise. The same is true if the belt isn't routed correctly on the pulleys. These belts today are very good and I haven't seen a bad belt out of the box yet. Hope this helps you.

Have a Nice Day     Mark