Dorman 419-365 Accessory Drive Belt Tensioner Assembly (Tensioner Only)

The Dorman 419-365 is a direct-fit automatic belt tensioner designed as a precise replacement for the original equipment tensioner on select BMW models. This tensioner-only unit maintains proper serpentine belt tension to keep accessory drive systems — including the alternator, power steering pump, and air conditioning compressor — operating reliably.

Engineered to match OE fit and function, this tensioner incorporates an internal damping mechanism, torsion spring, and integrated sealing system to deliver consistent belt tension under real-world operating conditions. It is an ideal solution when the original tensioner shows signs of belt slipping, excessive wear, noise, or fatigue.

Key Features:

• Direct OE replacement — designed to match the fit and function of the original equipment tensioner
• Internal damping design with torsion spring and sealing system for consistent, reliable belt tension
• Smooth tensioner pulley for quiet, efficient accessory belt operation
• Rigorously tested — quality testing includes torque, spring-back, corrosion resistance, and on-vehicle validation
• Durable construction — manufactured to strict specifications for long-term performance
• Sold individually — tensioner only (pulley bracket assembly not included)

Dorman recommends inspecting and replacing the belt tensioner any time the serpentine belt is replaced. Backed by Dorman's team of U.S.-based product experts and over a century of automotive aftermarket experience.