In most cars, the tension is derived from the small spring housing (that resembles a canister) and an arm for tensioning. The tensioner pulley’s belt is usually attached to these arms which then revolve all around the spring housing. This revolving motion is used to produce the constant tension that is so important to all vehicles. Tensioner pulleys perform a number of important functions. First of all, the tensioner pulley is used to maintain the proper levels of tension to the serpentine belt. This is known to extend the longevity of these serpentine belts. The tensioner pulleys are also important in preventing any slips of the belt. These slips are infamous since they reduce the amount of time that the belt will serve the needs of the vehicle. They also reduce the service life of all the accessories which surround the belt. Belts which slip are also very noisy and cause the improper functioning of the aforementioned accessories. Thirdly, the tensioner pulley is core to the reduction of the need to manually re-tension the serpentine belts periodically. This reduces the maintenance tasks needed for your car. Tensioner pulleys have spring coils inside them that apply the correct amount of pressure and force that is necessary to keep the belt tight. The tensioner additionally provides the ‘give’ that enables it to cushion and absorb any loads of shock hitting the belt which usually occur whenever the alternating current of the compressor clutches the cycles off and on. The tensioner also compensates for any wear to the pulley. Worn tensioner pulleys are usually the most probable reason behind most damages that occur to the belt system. Such damages include belts that have worn excessively, loss of tension to your pulley system, constant vibration and disenchanting misalignment. In conclusion, tensioner pulleys, like most other machine parts, do not last forever. The automatic tensioner and the serpentine belts should always be replaced at the very exact same time. This will reduce any problems that may arise with regard to the warranty of the belt, labor claims and comebacks.