Are you working on a 2006-2012 VW Jetta Diesel that has come in for repairs with a compressor drive pulley that has sheared and is spinning freely? There may be more to look at than the air conditioning system. These vehicles are equipped with an alternator decoupler pulley. This decoupler pulley is designed to transfer torque from the engine to the alternator from the pulley. It then “over runs” during deceleration to help run the alternator. It is also designed to absorb engine vibrations.
When the decoupler pulley becomes worn, it can create a whiplash effect. This whiplash effect caused extra tension on the compressor’s pulley. Due to the extra tension, the pulley can begin to shear and break free. When replacing this compressor, it would be good practice to replace the alternator decoupler pulley as well in order to reduce the possibility of a future comeback.
Information provided by: Global Parts Distributors
