Like all decoupler pulleys, the OAD disengages the alternator’s rotational mass from the belt drive when there’s sudden belt deceleration.  

An OAD pulley also features a sophisticated internal spring-and-clutch system (a damper) that absorbs the force generated by belt accelerations and tension reversals. By eliminating damaging peaks in belt tension, it can extend the life of belts, tensioners and other drive-belt components, and make for a smoother-running system. It also enables the engine to operate more efficiently, and helps minimize noise, vibration and harshness.

This video is sponsored by The Pronto Network.