What would make a serpentine belt come loose?

-My sister's 1999 Chevy Cavalier's belt came loose today. It has been crazy hot here in Ohio. She started the car and the battery warning light came on and when she opened the engine hood the belt was off completely. The car had some power steering pump work done about 2 years ago. The car has been having a rough idle.



The poor car is due to be junked next year. It has over 190,000 miles on the engine. It's still a good beater car for the time being. Once my sister receives her income tax refund she definitely getting a better car. My mechanic said that maybe the mechanic who did the work didn't reinstall the belt correctly. It's going to cost about one hundred dollars to get a new belt on the car.



The sad part of the story is that the mechanic who did the original work on the car is out of business so I can't sue him for his bad work. How long will it take to install a new belt? I know that the battery warning light came on because the alternator relies on the belt to power the engine. Did the mechanic give me a good price for the work? ThanksThe belt tensioner probably wasn't set correctly. It should be any easy fix for any shop... $100 sounds like a decent deal since any shop is going to charge you at least one hour of labor at anywhere between $70 to $100 per hour, plus the cost of the belt.



Why junk it just because of the miles? My 1998 Chevy pickup has 240,000mi and it's still chugging along. Take care of the car and it will last.Bad bearing on the idler pulley..... I knew achick who bought a second car......parking her van, over this $34 fix...