Hayden 5978 Accessory Drive Belt Idler Pulley

Hayden 5978 Accessory Drive Belt Idler Pulley

The Hayden 5978 accessory drive belt idler pulley is a direct-fit replacement for serpentine belt systems that need stable belt routing and consistent tension. Built with a black plastic pulley body and six grooves, it supports proper belt tracking on select Ford, Chevrolet, Pontiac, and Mercury applications.

Hayden Pulley products focus on OE-style replacement fitment for accessory drive belt system components. This idler / tensioner pulley is made to meet or exceed OEM requirements and is sized for applications that use a 6-groove serpentine belt.

Key Features

• Part number: 5978
• Accessory drive belt idler pulley for serpentine belt systems
• Black plastic construction
• 6-groove pulley design
• Outside diameter: 5.1875 in. (131.763 mm)
• Inside diameter: 1.000 in. / bore diameter: 0.668 in. (17 mm)
• Pulley width: 1.062 in. (27 mm)
• Meets or exceeds OEM requirements
• Mounting hardware not included

Product Details

Hayden 5978 is an idler / tensioner pulley designed for accessory drive belt systems that use a serpentine belt with a 0.3125 in. (7.9375 mm) belt width. The pulley’s 6-groove profile helps maintain belt alignment across the drive path, while the 27 mm width and 131.763 mm outside diameter match the listed OE-style dimensions. This part cross-references Dayco 89013 and Dorman - HELP 38029 for the same application.

Fits 1994-2000 Ford Mustang, N/A; Fits 1987-1993 Ford F-250, N/A; Fits 1988-1993 Ford F-350, N/A; Fits 1988-1992 Chevrolet Camaro, N/A; Fits 1989-1992 Pontiac Firebird, N/A; Fits 1990 Chevrolet S10, N/A; Fits 2004 Mercury Mountaineer, N/A.

Common Uses

• Replacing a worn or noisy serpentine belt idler pulley
• Restoring proper belt routing on accessory drive systems
• Addressing belt squeal caused by pulley wear or surface damage
• Correcting belt tracking issues related to pulley groove wear
• Servicing OE-style belt drive components on Ford, Chevrolet, Pontiac, and Mercury vehicles

Installation Notes and Tips

Verify pulley diameter, groove count, and belt width before installation to confirm match with the existing accessory drive layout. Mounting hardware is not included, so reuse or source the correct fastener as needed. Inspect the serpentine belt, tensioner, and adjacent pulleys during service to avoid repeat belt noise or premature wear.

Quality Assurance

Hayden 5978 is listed as meeting or exceeding OEM requirements for the specified applications. Confirm fitment against the vehicle’s belt drive configuration, especially on 1987-1987 Ford applications noted without air conditioning and on 1988-1989 Ford F-250 and F-350 applications with assembly number ETA19A216-AA.