GMB 425-8490 Engine Timing Belt Tensioner

Engine Timing Belt Tensioner for Ford and Mazda

GMB 425-8490 is an engine timing belt tensioner built to meet or exceed OEM specifications. It is engineered for timing belt systems that use a serpentine and V-belt pulley profile, with a metal pulley construction for dependable operation in the valve train system.

Compatible With Ford Ranger, Ford Mustang, Ford Aerostar, Ford LTD, Ford Thunderbird, Mercury Capri, Mercury Cougar, Mercury Marquis, Ford Fairmont, Mercury Zephyr, Ford Courier, Ford Pinto, Mercury Bobcat, Mazda B2500, and Mazda B2300 applications across the listed model years.

• Engine timing belt tensioner for valve train service
• Metal pulley construction
• Serpentine and V-belt pulley type
• 1 mm drive belt pulley diameter (1)
• 1 pulley groove quantity (1)
• Built to meet or exceed OEM specifications

Detailed Product Overview

The GMB 425-8490 timing belt tensioner is a direct-fit engine component for a wide range of Ford and Mazda vehicles. It is used in timing belt-driven engine systems where consistent belt control is needed to maintain proper valve timing and reduce belt slack. This part cross-references Gates T41005 for the same application.

Vehicle coverage includes Fits 1983-2001 Ford Ranger, N/A; Fits 1998-2001 Mazda B2500, N/A; Fits 1994-1997 Mazda B2300, N/A; Fits 1979-1993 Ford Mustang, N/A; Fits 1986-1987 Ford Aerostar, N/A; Fits 1983-1986 Ford LTD, N/A; Fits 1983-1986 Ford Thunderbird, N/A; Fits 1979-1986 Mercury Capri, N/A; Fits 1975-1977 Mercury Capri, N/A; Fits 1984-1986 Mercury Cougar, N/A; Fits 1981-1982 Mercury Cougar, N/A; Fits 1983-1986 Mercury Marquis, N/A; Fits 1978-1983 Ford Fairmont, N/A; Fits 1978-1983 Mercury Zephyr, N/A; Fits 1977-1982 Ford Courier, N/A; Fits 1974-1980 Ford Pinto, N/A; Fits 1975-1980 Mercury Bobcat, N/A.

What This Part Helps Address

• Timing belt slack or inconsistent belt tension
• Noise from a worn or rough tensioner pulley
• Improper belt tracking in the timing system
• Service replacement for worn valve train tensioner components
• Fitment needs for Ford Ranger and Ford Mustang timing belt applications

Installation Notes and Tips

Verify engine application, belt routing, and pulley alignment before installation. Inspect the timing belt, related pulleys, and adjacent wear components during service, since a new tensioner performs best with a properly matched belt system. Confirm the part number 425-8490 against the vehicle’s engine configuration before assembly.

Quality Assurance

GMB manufactures this tensioner to meet or exceed OEM specifications, supporting consistent fit and function for the listed Ford and Mazda applications. Part number 425-8490 is also referenced as 4258490 and D4FZ6K254A in interchange data.