Tensioner
A Drive Belt Tensioner is a pulley mounted to either a spring mechanism or to an adjustable pivot point that is used to keep constant tension on your serpentine belt.
It is made up of four main parts – the base, tensioner arm, spring and pulley. The base holds the other parts, and the spring keeps the belt pulled tight. The pulley is what facilitates movement of the belt. The tensioner arm is found on the bottom of the tensioner, and if you press on it, it will work against the spring, delivering enough slack so that you can adjust or remove the belt.
