Xiaoyudou Serpentine Belt Drive Kit for BMW 3.0L L6 (2006–2013) — Tensioner, Idler Pulley, Belt & Bolt, Reinforced Bearings

Xiaoyudou complete drive kit replaces worn belt tensioner, idler pulley, serpentine belt and tensioner bolt for BMW 3.0L L6 engines (2006–2013) to restore reliable accessory drive operation.

This all-in-one replacement set contains a belt tensioner, idler pulley, serpentine belt and tensioner bolt engineered to match the fit and function required by many BMW 3.0L inline-six applications. Each component is built from reinforced materials and inspected before shipping to reduce vibration, limit belt slip and return consistent accessory drive tension. The kit replaces multiple OE numbers so you can quickly swap a single package for common worn parts during scheduled service or when diagnosing drive‑belt noise and wear.

Which BMW models and part numbers does this kit replace?

This kit is designed to fit BMW 3.0L L6 models from the mid-2000s through early 2010s, covering many variations of the 1-, 3-, 5-series and X3 with that engine. It directly replaces several original equipment numbers for tensioners, idler pulleys, the belt and the mounting bolt for straightforward interchangeability.

• Compatible models include BMW 128i (2008–2013), 323i (2006–2011), 325i/325xi (2006), 328i/328xi (2007–2013), 330i/330xi (2006), 525i/525xi/528i/528xi/530i/530xi (2006–2010) and X3 (2007–2010) with 3.0L L6 engines.
• Replaces tensioner numbers: 39112, 11288624196, 11287530314, 28708, 305399, 89399.
• Replaces idler numbers: 11287535860, 89163, 36369; belts: 6K1990, 11287628650, 11287549150, W01331681440, W01331779583.
• Tensioner bolt replacement: 11287530315.

How does the kit improve drive-belt performance and noise?

Replacing worn tensioners and idler pulleys restores correct belt alignment and tension, reducing slippage and uneven wear that commonly cause squeal and vibration. The reinforced construction and quality bearings lower noise and help maintain steady accessory operation under load.

• New tensioner restores proper spring tension and preload for the belt system.
• Smooth idler pulley bearings reduce wobble and drivetrain vibration.
• Fresh serpentine belt with correct rib profile improves grip and accessory drive efficiency.
• Tensioner bolt ensures secure mounting and correct torque retention.

What’s included and what should I inspect during installation?

The package supplies everything needed to refresh the belt drive: one tensioner, one idler pulley, one serpentine belt and a tensioner bolt. During installation check pulley alignment, belt routing, accessory pulleys and engine mounts for wear to prevent premature return of symptoms.

• Included in box: belt tensioner, idler pulley, serpentine belt, tensioner bolt.
• Inspect alternator, A/C compressor and water pump pulleys for roughness or play.
• Verify belt routing and rib alignment before torquing the new tensioner bolt.
• Replace any cracked hoses or worn mounts found during access for long-term reliability.

How durable is the Xiaoyudou kit and what warranty is offered?

Components are produced from reinforced materials and undergo testing to reduce vibration and runout; proper installation helps achieve expected service life comparable to aftermarket standards. Xiaoyudou supports the kit with a two-year warranty against manufacturing defects—contact customer service for replacement guidance if issues arise.

• Reinforced materials and pre-shipment testing to control vibration.
• Two-year warranty for defects, with replacement support from the brand.
• Recommended to follow service intervals and inspect associated components for best longevity.

Who is this for: This kit is aimed at owners and independent technicians servicing BMWs with the 3.0L inline-six who need a single, vehicle-specific package to replace worn belt-drive components. It’s a practical choice for routine maintenance, restoring proper belt tension after pulley failure, or performing preventative replacement during larger engine or front-end service intervals.