Surpentine belt change on '97 Riviera

Can anyone out there tell me the GM recommended mileage at which the main Serpentine belt and Supercharger belt should be changed on my '97 Riviera? The car has 80,000 miles and still has the original belts. Should any of the idler pulleys or tensioners also be changed as a precautionary measure?

take your belt and look at it in the sun or a light. Are there any cracks in the ribs of it? really shiny spots? if not, it's fine. As for the tensioners, let the engine run and look at it, if it wobbles just a little bit, its fine. A lot then you should replace it. Tensioners and belts are tricky. If you like to floor it alot, the belt and tensioner will wear out alot quicker than if you drive on the interstate alot and take your time getting up to highway speeds.