Most cars now have a serpentine belt drive. It powers several accessories such as the air conditioner compressor, water and power steering pumps, fan, and even the booster for the braking system.
You should have the serpentine drive belt system checked periodically. If it fails, the engine will overheat, and worse, the car won't run. The situation could leave you stranded on a highway or busy metropolitan street waiting for a costly tow to a local repair shop.
Listen for signs of impending belt failure. A squealing noise when the car accelerates means the belt is slipping and is not efficiently turning the drive accessories. The belt tensioner also could be worn and in need of immediate replacement. Look for excessive cracks in the gelt's V-ribs, and chunks that have broke off the ribs. Visual appearance is not a reliable indicator of the expected service life of a belt. It is recommended that you replace the serpentine belt every four years.