A drive belt or serpentine belt is tensioned by a automatic belt tensioner. The tensioner is the component that keeps the proper amount of tension on the belt while the engine is running. The belt travels under the pulley that is attached to the automatic belt tensioner. As the engine is running, the spring inside of the tensioner moves up and down with the movement of the belt. Once that the spring inside of the spring loaded arm becomes weak, it will not keep the proper amount of tension on the belt.
Park the vehicle in a safe working environment and open the hood.
Locate the automatic belt tensioner on the front of the engine. The tensioner is made up of a pulley on one end and a spring loaded arm on the other end. Locate the bolt head that is located in the middle of the tensioner pulley. If there is no bolt, then locate the square hole on the top of the spring loaded arm of the automatic belt tensioner.
Pivot the automatic belt tensioner from the bolt head or the square hole counter clockwise with the breaker bar and socket to loosen the tension on the belt. Reach down with the other hand and slide the belt off of the tensioner pulley with your free hand.
Slowly allow the automatic belt tensioner to retract until it stops. Then, locate the automatic belt tensioner mounting bolt. This bolt connects the tensioner to the engine block. The bolt is located in the middle of the spring loaded arm.
Turn the automatic belt tensioner mounting bolt counter clockwise with the ratchet and socket to loosen. Then, finish unscrewing the bolt with your fingers. Pull the belt tensioner straight off of the engine block.
Position the new automatic belt tensioner onto the engine block and screw the mounting bolt back in. Tighten the mounting bolt with the ratchet and socket.
Pivot the tensioner pulley counter clockwise with the breaker bar and socket. Then, slide the belt onto the new automatic belt tensioner pulley. Slowly release the tensioner pulley and it will retract until it stops. Once the tensioner stops, the belt will be at the proper tension.
Inspect the new tensioner and make sure that the belt is properly routed under the tensioner pulley. Also make sure that the belt did not come out of any of the other accessory pulleys. Then, crank the engine and watch the new tensioner while the motor is running to see it is going to function properly. Turn the engine off and close the hood.
