Tensioner Pulley

A tensioner is found in cars with serpentine belt front end drives. It is used for several things.

• First, it maintains the proper tension of the serpentine belt which subsequently extends the life of the belt.

• Second, the belt tensioner pulley prevents belt slips. Belt slips can reduce service life of belt and the surrounding accessories.

• Lastly, a tensioner belt can reduce the need for periodic manual re-tensioning of the serpentine belt.

The tensioner pulley is composed of several individual parts that can perform an ultimate task when combined. These include the base, a damping mechanism, the tension spring, the arm, the pulley or bearings, the sealing disk, and the bolt. The parts are also made of different materials, all of which have their own pros and cons.

The raw materials used to create the pulley are important options when opting for a purchase. A belt tensioner pulley can be made of two materials: plastic and metal. These materials have their own advantages and disadvantages. Apart from the advantage and disadvantages, the choice you make is critical to how your car runs. 

Regarding the tensioner spring, there are two main types of spring construction design. The first one is a round torsional spring. The second is a flat torsional spring. Round torsional springs create tension through a series of rotations in contrary to how flat torsional springs are designed. Flat torsional springs create tension by coiling which can produce excessive heat that can be damaging for the tensioner. 

Before you go off buying a replacement tensioner pulley, you have to be aware of the different advantages and disadvantages of the materials and the designs of the parts. 

Here are some differences between the two makes of the pulley. A plastic pulley retains heat longer while a steel pulley disperses and distributes heat more evenly. A plastic pulley accumulates dirt and grime while a steel pulley deflects those elements.

In addition, a plastic pulley is more inviting to abrasion while a steel pulley resists abrasion. Lastly, plastic bearings of a plastic pulley become distorted with prolonged use while those of a pulley retain their roundness. Obviously a steel pulley has more advantages than a plastic pulley.    

The spring provides constant belt tension and is an important part of the tensioner. The round torsional spring is noise and vibration free. This design has spaces between coils that keep them from banging together. A flat torsional spring keeps the coils closely wrapped causing a lot of vibration. As the belt tensioner pulley with a round spring wears down, it becomes noisier. A round torsional spring is preferable since it provides quiet operation in automobiles.  

Your car is second most expensive purchase you will make in your life. It is important that you take good care of it. Using a reliable and well designed tensioner pulley will surely prolong the service life of the serpentine belt.