Dayco 892009 Overrunning Alternator Decoupler Pulley OAP OAD

The Dayco 892009 is a direct-fit Overrunning Alternator Decoupler Pulley (OAP / OAD) engineered to handle the increased electrical demands placed on modern vehicle charging systems. As late-model vehicles have added more power-hungry accessories, alternator loads and engine torsional fluctuations have grown significantly — making a properly functioning decoupler pulley critical to drive system health.

This pulley features a one-way clutching mechanism that isolates and dampens the drive from the alternator during deceleration, allowing the alternator to freewheel rather than abruptly stop with the belt. Upon acceleration, the pulley smoothly re-engages, protecting the entire front-end accessory drive system from shock loads.

Key Features:

• Outside diameter: 55.9 mm; width: 35.6 mm
• One-way clutch design reduces belt noise and slippage during rapid acceleration and deceleration
• Improves drive belt tension consistency, extending belt and alternator service life
• Grooved pulley surface for positive serpentine belt engagement
• Sold as a single unit — direct replacement for the OEM decoupler pulley
• 2-year warranty

Cross-Reference Part Numbers: Audi 06B903119B, Audi 06B903119D, Gates 37044P, Gates 37103P, INA 535004110, Ruville 55721, Bosch F 00M 147 732, Bosch F 00M 991 108, Bosch F 00M 991 266, INA F 231142, SKF VKM03116.

Common symptoms of a failing OAD include unusual serpentine belt noise, vibration, failure of the alternator to charge the battery, or a pulley that spins freely in both directions. The Dayco 892009 restores proper decoupler function and is backed by Dayco's reputation for quality powertrain components since 1905.