The serpentine drive belt system is kept tightly around all of the components it supplies power to, with the use of the Pontiac Drive Belt Tensioner and Drive Belt Pulley.
The drive belt tension and pulley are in place so the slack of the serpentine belt is taken out and the belt can keep in firm contact with the other pulleys on the front of your Pontiac engine. It is the friction that the drive belt pulley and tension place on the polymer drive belt that holds it in place and makes it possible for the accessories to be supplied with centrifugal power so they can operate.
To identify the Pontiac drive belt pulley and tension, the owner only needs to look for the stand alone pulley on their serpentine drive belt system. It is generally near the top of the belt drive system and is easily accessed so the tension of the belt can be taken off so the belt can be easily changed out when it is required. There is also a large bolt head in the center where the socket and breaker bar is placed to relieve the tension so the belt can be taken off of the Pontiac engine assembly.
The drive belt tensioner and pulley will be in need of replacement when its ability to provide the force against the serpentine belt is not longer sufficient for enough friction to be applied against the belts and the pulleys of the accessories so they can receive the centrifugal power. This force is provided by the coiled spring in the makeup of the pulley and can be noticed to longer providing the required force when the Pontiac engine is running and the belt system appears to be loss.