Gates 20504 Radiator Coolant Hose - Upper

Gates 20504 Molded Coolant Hose Overview

The Gates 20504 molded coolant hose is built for radiator coolant and heater circuit service where a formed hose shape is needed for proper routing. Made from EPDM and molded to OEM-style dimensions, it supports upper hose applications on select Buick Skylark, Chevrolet Nova, Oldsmobile Omega, Pontiac Phoenix, and other classic GM and Dodge vehicles.

Gates Molded Coolant Hose line is a broad replacement range for upper, lower, bypass, heater, and related cooling-system applications. This part number, 20504, is part of that molded hose family and is listed for multiple vintage vehicle applications where a formed hose or cut-to-fit routing is required.

Key Features

• EPDM construction for cooling-system service
• Molded hose design for formed routing
• 1.5 in. inside diameter at both ends
• 23 in. centerline length
• No spring and no quick-connect fittings
• OEM-quality specification for radiator coolant hose replacement

Detailed Product Description

Gates 20504 is a molded radiator coolant hose with a 1.5-inch inside diameter at each end and a 23-inch centerline length. The EPDM material is commonly used in engine cooling systems for its resistance to heat and coolant exposure. Its molded shape helps maintain the intended hose path in upper radiator and heater-related routing on listed applications.

Fits 1977-1979 Buick Skylark, upper; fits 1975-1979 Chevrolet Nova, upper; fits 1977-1979 Oldsmobile Omega, upper; fits 1977-1979 Pontiac Phoenix, upper. It also appears in fitment for classic GMC vans and Chevrolet Suburban models, along with select Buick Skylark, Chevrolet Blazer, Dodge Challenger, Dodge Charger, and Oldsmobile Cutlass applications. This part cross-references Dayco 70392 and Four Seasons 20504 for the same application.

Common Problems This Hose Can Address

• Cracked or hardened upper radiator hose
• Coolant leaks from aged EPDM or rubber hose material
• Poor hose routing caused by a collapsed or misshaped hose
• Cooling-system service on vehicles requiring a molded replacement
• Fitment issues when a straight universal hose will not follow the original path

Installation Notes and Tips

Verify the vehicle’s cooling-system layout before installation, especially on applications noted as cut-to-fit or requiring trimming. Confirm the hose end diameters and centerline length against the original hose routing, and inspect clamps, necks, and adjoining cooling components for wear before assembly. For vehicles listed with upper-position fitment, install the hose in the original routing path to maintain clearance around belts, pulleys, and engine accessories.

Quality Assurance

Gates manufactures molded coolant hoses to OEM-quality specifications for radiator, heater, bypass, and related coolant applications. The 20504 is part of Gates’ molded hose replacement line, which is built to cover a wide range of cooling-system service needs across classic GM and Dodge fitments.