Dorman 419-365 Accessory Drive Belt Tensioner Assembly

Overview of Dorman Accessory Drive Belt Tensioner Assembly

The Dorman 419-365 accessory drive belt tensioner assembly is engineered for reliable performance in select BMW models. Designed with durable aluminum and plastic components, this tensioner ensures proper serpentine belt tension for optimal engine operation in BMW 125i, 128i, and 325i vehicles.

• Constructed from lightweight aluminum for strength and corrosion resistance
• Includes one automatic belt tensioner and one mounting bolt for installation
• Features a single plastic pulley with a 40 mm bearing diameter
• Designed for serpentine belt systems with a maximum adjustment range of 180 degrees
• Compatible with BMW 125i, 128i, and 325i models
• Part number 419-365 ensures exact fit and function

Detailed Product Description and Specifications

This Dorman accessory drive belt tensioner assembly (part number 419-365) is specifically designed to maintain proper tension on the serpentine belt in BMW 125i, 128i, and 325i models. The tensioner body is made from aluminum, providing a balance of durability and lightweight construction. It features a black and silver finish, with an overall length of 145 mm, an outside diameter of 70 mm, and an inside diameter of 17 mm. The tensioner includes one mounting hole with a 12 mm diameter, facilitating secure attachment to the engine assembly.

The tensioner pulley is made of plastic and contains a single bearing with a 40 mm diameter, designed to rotate clockwise (CW) to maintain belt tension. This assembly supports serpentine belt systems without grooves on the pulley, ensuring smooth operation and reducing wear on the belt. The maximum adjustment range of 180 degrees allows for precise tension control, which is critical for maintaining engine accessory performance.

Compatible Vehicles and Applications

• BMW 125i
• BMW 128i
• BMW 325i

This accessory drive belt tensioner assembly is compatible with the above BMW models, providing a direct replacement for worn or damaged tensioners to restore proper belt tension and accessory drive function.

Common Issues Addressed by This Tensioner Assembly

• Eliminates belt slippage caused by insufficient tension
• Prevents premature serpentine belt wear and cracking
• Reduces noise from loose or misaligned belts
• Maintains proper accessory drive system performance
• Helps avoid engine overheating due to accessory failure

Installation Notes and Tips

Installation of the Dorman 419-365 tensioner assembly requires removal of the old tensioner and proper alignment of the serpentine belt. Use the included mounting bolt to secure the tensioner in place. Ensure the tensioner rotates clockwise as designed and verify belt tension after installation. It is recommended to inspect the serpentine belt for wear and replace it if necessary during installation.

Quality Assurance and Warranty

Dorman manufactures this accessory drive belt tensioner assembly to meet or exceed OEM specifications for fit, form, and function. The aluminum construction and quality bearing components contribute to long service life. This part is backed by Dorman's standard warranty coverage, providing assurance of reliability and performance for BMW 125i, 128i, and 325i owners.