The belt tensioner is the component that tensions the belt, keeping the proper amount of tension on the belt while the it travels around each accessory pulley. When the motor is running, the belt is driven around all of the accessory pulleys by the crankshaft pulley. As the belt is turning around each pulley, the tensioner springs up and down with the movement of the belt to keep the belt properly tensioned. Replace the tensioner once the spring inside of it becomes weak or if it breaks.
Tools Used: Tools, 1/2-inch drive ratchet, 1/2-inch drive extension, Metric socket set, Bungee strap, Replacement tensioner with bracket
Change Serpentine Belt Tensioner
Open the hood and locate the tensioner. The tensioner for the 1993 Buick Century 3.3 models is located near the front-center of the engine. The tensioner has a small pulley attached to a spring-loaded arm. The tensioner is also attached to a tensioner bracket that is mounted to the front of the engine.
Rotate the tensioner pulley from the bolt head in the center of the pulley counterclockwise with the ratchet and socket. Pull the belt off the tensioner pulley only. Position the bungee strap around the belt and one of the holes in the water pump pulley so that it does not come out of the other accessory pulleys. Loosen and remove the bolt from the spring-loaded arm of the tensioner with the ratchet and socket by turning the bolt counterclockwise. Pull the bolt out and place it to the side.