Belt Idler Pulley – 11 28 8 673 720 (INA)

Description

Product Description

The 11 28 8 673 720 Belt Tensioner by INA (Schaeffler) is an OE‑quality accessory drive tensioner used on select BMW engines. The tensioner maintains the correct serpentine belt tension as the engine runs, compensating for belt stretch and damping vibration to keep the belt tracking properly and driving critical accessories such as the alternator, A/C compressor, and power steering pump (where equipped).

Over time, the internal spring mechanism can weaken and the pulley bearing can wear, leading to belt noise, belt flutter, or premature belt wear. In severe cases, a failing tensioner can cause belt misalignment or belt loss. Replacing the unit with this INA 11 28 8 673 720 tensioner restores proper belt tension, quiet operation, and reliable accessory drive performance.

• OEM reference: 11 28 8 673 720
• Brand: INA (Schaeffler) – original equipment supplier for BMW belt drive components
• Maintains consistent belt tension for stable accessory operation
• High‑quality pulley bearing for smooth, quiet rotation
• Durable spring and damping design to reduce belt vibration
• Direct‑fit replacement for correct alignment and easy installation

Applications

Used on select BMW models/engines that specify belt tensioner part number 11 28 8 673 720.

(Fitment varies by engine family and model year—confirm by VIN or catalog.)

Service Notes

• It’s often recommended to replace the serpentine belt when replacing the tensioner.
• Inspect idler pulleys and belt routing components for wear or noise.
• Confirm proper belt alignment and tension after installation.

Additional information