Dorman 419-120 Accessory Drive Belt Tensioner Assembly

Reliable Accessory Drive Belt Tensioner for Buick and Chevrolet Vehicles

The Dorman 419-120 accessory drive belt tensioner assembly is engineered to maintain optimal tension on serpentine belts in select Buick, Chevrolet, Oldsmobile, and Pontiac models. Designed for durability and precise fitment, this tensioner supports smooth engine operation and accessory performance.

• Compatible with Buick 88, 98, LeSabre, Park Avenue, and Riviera models
• Fits Chevrolet Lumina APV, Silhouette, and Trans Sport vehicles
• Serpentine belt type with a single pulley design
• Polyamide 6.6 pulley reinforced with 30% glass fiber for strength
• Clockwise (CW) tensioner rotation for proper belt alignment
• Pulley outside diameter: 83 mm; inside diameter: 17 mm
• Single pulley bearing with a 40 mm diameter for smooth operation
• Part number 419-120 ensures exact replacement fit

Detailed Specifications and Design Features

The Dorman 419-120 accessory drive belt tensioner assembly features a robust polyamide 6.6 pulley reinforced with 30% glass fiber fill, providing enhanced durability and resistance to wear. The pulley measures 83 mm in outside diameter and 17 mm inside diameter, with a width ranging between 20 mm and 26.3 mm, accommodating serpentine belts used in various GM vehicles. This tensioner includes a single pulley with one bearing, sized at 40 mm in diameter, designed to reduce friction and extend service life. The clockwise rotation mechanism ensures proper belt tension and alignment, critical for maintaining accessory drive system performance.

Compatible Vehicles and Applications

This accessory drive belt tensioner assembly is compatible with multiple General Motors models, including Buick 88, 98, LeSabre, Park Avenue, and Riviera, as well as Chevrolet Lumina APV, Silhouette, and Trans Sport. It also fits Oldsmobile and Pontiac models such as Bonneville, Regal, and Toronado. The Dorman 419-120 is specifically designed for serpentine belt systems in these vehicles, providing a direct replacement for worn or damaged tensioners.

Common Issues Addressed by the Dorman 419-120 Tensioner

• Eliminates belt slippage caused by insufficient tension
• Prevents premature belt wear and cracking
• Reduces noise from loose or misaligned belts
• Restores proper accessory drive function for alternators, power steering, and A/C compressors
• Mitigates risk of belt failure leading to engine overheating or loss of electrical charging

Installation Notes and Tips

When installing the Dorman 419-120 tensioner, ensure the serpentine belt is properly routed according to the vehicle’s belt diagram. Use appropriate tools to relieve tension from the old tensioner and carefully align the new unit to avoid misalignment. Verify the clockwise rotation direction matches the original part. Inspect the belt for wear and replace if necessary to ensure optimal performance. Torque all mounting bolts to manufacturer specifications.

Quality Assurance and Warranty Information

Dorman manufactures the 419-120 accessory drive belt tensioner assembly to meet or exceed OEM standards for fit, form, and function. The use of reinforced polyamide materials and precision bearings contributes to long service life. This part is backed by Dorman’s limited warranty, providing coverage against defects in material and workmanship under normal use conditions.