<P> It is more efficient than the older multiple belt system and may consume less space in the engine compartment . By using a single, wider belt instead of multiple, thinner belts, the belt may be put under increased tension without stretching . Higher tension reduces slip, which increases belt life and mechanical efficiency . Reduced slip can allow the use of lower - ratio pulleys; this reduces the load on the engine, increasing fuel economy and available power . The tendency for V - belts to "flip over" in the pulley groove (at high RPM and / or when the belt stretches) is eliminated, and a serpentine belt is also much easier to maintain and replace, since there is no need to remove multiple belts in order to replace one of them, although newer adjustable - length V - belts ("link belts") can be put on without having to remove other belts, and their link design also allows a self - tensioning characteristic to reduce the risk of flipping over . Also since only one movable belt tensioner is required all of the peripheral components (alternator, A / C compressor, etc .) can simply be mounted to the engine without the need to swivel . </P> <P> The drawback of this single belt is that if the belt breaks or is knocked loose, the vehicle instantly loses multiple critical functions . The water pump, power steering pump, and alternator (for battery charging) would cease functioning . The vehicle becomes quickly unusable due to loss of engine cooling . The belt typically gives ample visual warning of impending failure, sometimes even totally shedding several grooves (ribs) while continuing to function acceptably . </P>

How many serpentine belts are in a car