Ensuring optimum tension in drive and timing belts is the job of tensioners, idlers and dampers. These essential devices can wear over time. We have a full range of tensioners, idlers and dampers for all types of car.
All cars have a drive belt, which powers parts such as the alternator, air-conditioning compressor, power steering and, sometimes, the water pump. Most cars also have a timing belt, which synchronises the opening and closing of the engine's valves. Both these belts need to be kept at the correct level of tension so they do not become loose. The tensioner applies force to prevent the drive and timing belts from becoming slack. It comprises a base, tensioner arm, spring and pulley, which work together to deliver the right amount of tension needed by the belt in order to drive the engine components. Some tensioners are manually adjusted, while others are automatic. A worn tensioner can cause serious damage to the belt. The idler is a rotating pulley that controls the movement of the belt from the crankshaft to power the various engine parts. It is one of a set of pulleys that support the belt. If it becomes worn you might notice a squealing sound coming from the engine. Visual signs of wear include score marks on the idler's surface, or even cracks or breaks. The damper in older engines is a hydraulic mechanism that dampens vibrations by means of a spring tensioner unit. In newer engines, a friction damper works alongside an inbuilt torsion spring in the tensioner wheel. Essentially, the damper is a shock absorber. It needs to be replaced if worn to ensure smooth running of the belt. Show Less