ACDelco stands for quality. Get the performance you need with ACDelco products. The ACDelco Heavy Duty Automatic Belt Tensioner is equipped with a patented design that provides superior belt alignment and tension for improved drive efficiency and life. Its damping mechanism provides maximum stability, reducing vibration and increasing the life of the belt, tensioner, and other accessory drive components. ACDelco products are developed to exceed your performance expectations and deliver the durability you expect.