After hearing about significant installation issues with tensioners from multiple repair technicians on Detroit Diesel 13 and 15 series engines, Dayco, an engine products and drive systems specialist for the automotive, heavy-duty, and industrial market segments, designed and engineered a two-piece tensioner to help address high failure rates and installation problems with the original equipment design.  

With more than 500,000 vehicles in operation, the DD13 and DD15 series engines are popular in Class 8 and other applications. The engine uses a competitor’s dual tensioner assembly as original equipment, meaning a one-piece tensioner that keeps tension on two belts. However, reports from distributors and repair shops suggest the original OE tensioner was not only a large heavy unit, it was also failure prone. While the OE unit has since been upgraded, it is still difficult to install. Technicians are required to bend an 8-rib belt sideways through a very narrow opening during replacement, which can lead to belt issues if not done carefully. 

Instead of struggling to get the belts on a one-piece tensioner, Dayco split the system in two, so the product has an outer and inner tensioner that cuts installation time in half.  

The Dayco 89947 heavy duty two-piece tensioner is machined from high strength steel or powdered metal to provide wear resistance under harsh environments. It features Dayco’s flat spring technology and dual pressed-in pulley bearings to provide long bearing life and protection against the shock loads.

The Dayco 89947 heavy duty two-piece tensioner will be included in three different serpentine belt kits designed for DD13 and DD15 engines, and can also be ordered as a standalone tensioner.