Product Details: Ensure your vehicle is Ready for the Road Ahead™ with optimized drive belt tension, with the Dayco 89490™ Heavy Duty Automatic Belt Tensioner. Thanks to its straightforward design, this replacement tensioner is able to help create the correct amount of tension on drive belts, delivering ample amounts of power to engine accessories such as water pumps, AC compressors, steering pumps, and alternators. Signs and symptoms that show a tensioner needs to be checked or removed include squeals, rattling sounds, chirps, or visible frays on a belt. FleetPride is your First Click in Heavy Duty®.