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This balancer pulley, also called vibration damper, drives the accessory belts for the 5 VW cylinder engines (2.4, 2.5 TDI). Attached to the crankshaft it may drive two v-belts or one ribbed (serpentine) belt. See choices below. The rubber in it can age and crack which can lead to a failure of this part which will destroy the ribbed belt for alternator and accessories.
Part Numbers: 074105251AC, 074105251J, 074105251N