Have You Replaced Your Timing Belt Lately? Most timing belts should be replaced every 50,000 to 60,000 miles. The timing belt is an essential part of the engine. If your timing belt breaks your engine will stop working and could cause major engine damage. Timing belts are not used in all automobiles. The serpentine or drive belts are sometimes used exclusively by a vehicle to provide all the power necessary for its accessories. Other automobiles use a combination of the serpentine belt and drive belts to power vehicle accessories.