Dayco 89941 Accessory Drive Belt Tensioner Assembly

Accessory Drive Belt Tensioner Overview

This Dayco accessory drive belt tensioner assembly is built for serpentine belt systems that require automatic belt control. It is a fitment-based replacement for heavy-duty truck applications, including Mack and Volvo models, and uses a single pulley design with a counter-clockwise rotation.

Part number 89941 is specified for accessory drive belt service where consistent belt tension is needed across fan, alternator, air conditioning, and water pump drive applications. The automatic design helps maintain belt tracking and tension without manual adjustment.

Key Features

• Automatic tensioner assembly for serpentine belt systems
• Counter-clockwise rotation
• Single pulley design with a 74 mm pulley diameter
• Flat pulley surface with 38 mm pulley width
• Fits multiple Mack and Volvo heavy-duty truck applications

Fitment Details

Compatible with 2020-2024 Mack TerraPro, fan; 2021-2022 Mack Anthem, fan; 2018-2022 Mack Granite, fan; 2019-2022 Mack Pinnacle, alternator; 2022 Volvo VNL, alternator and air conditioning; 2022 Volvo VNR, alternator and air conditioning; 2021 Volvo VNL, alternator; 2018-2021 Volvo VNR, fan; 2021 Volvo VNX, alternator; 2018-2020 Mack Anthem, alternator; 2019-2020 Volvo VAH, alternator; 2020 Volvo VHD, alternator; 2015-2020 Volvo VNL, fan; 2019-2020 Volvo VNX, fan; 2018-2019 Mack CXU, fan; 2014-2016 Mack CXU, fan; 2014-2019 Mack GU7, fan; 2014-2019 Mack GU8, fan; 2019 Mack MRU, alternator; 2019 Mack TerraPro, alternator; 2016-2019 Volvo VAH, fan; 2016-2019 Volvo VHD, fan; 2018 Mack CXU, alternator; 2018 Volvo VNM, alternator and air conditioning; 2015-2017 Mack MRU, fan; 2015-2017 Volvo VNM, fan; 2014-2016 Mack CXU, fan and water pump; 2015-2016 Mack LEU, fan; 2016 Mack LR600, fan; 2002 Western Star 4900E, fan and air conditioning.

Installation Notes

Verify belt routing, pulley alignment, and rotation direction before installation. Confirm the application by matching the vehicle position and drive accessory configuration to part number 89941. Replace the tensioner when belt tension control is inconsistent, the pulley shows wear, or the assembly no longer maintains proper belt tracking.

Quality Assurance

Dayco manufactures belt drive components for demanding accessory drive systems, and this tensioner is engineered for automatic belt control in heavy-duty service.