Dayco 70459 Engine Coolant Bypass Hose

Dayco 70459 Curved Radiator Hose

Dayco 70459 is a curved radiator hose built for engine coolant bypass service in a wide range of classic Buick, Chevrolet, GMC, Oldsmobile, Pontiac, and Jeep applications. Made from EPDM and formed as a single I.D. hose, it provides a direct-fit cooling system replacement for vehicles that need a 19/32 in. inside diameter at both ends.

Key Features

• EPDM construction for cooling-system use
• Black curved radiator hose profile for routed engine bay layouts
• Single I.D. hose with 19/32 in. inside diameter at both ends
• Built to SAE J20R4 Class D-1 and SAE J1684 Type EC specifications
• Fits a broad range of GM and Jeep applications, including Buick LeSabre, Chevrolet S10, and Pontiac Grand Prix
• Dayco 70459 is listed as an engine coolant bypass hose in the Belts and Cooling > Hoses and Pipes category

Product Details

The Dayco Curved Radiator Hose line is focused on shaped coolant hoses that follow factory routing and help maintain proper coolant flow through the engine cooling circuit. Part number 70459 is a curved hose with a 4 1/2 in. trunk height and no heat shield or protective sleeve, making it a straightforward replacement for vehicles that use this hose geometry. This part cross-references Gates 20521 for the same application.

Compatible vehicle coverage includes Fits 1984 Buick LeSabre, N/A; Fits 1984 Buick Regal, N/A; Fits 1983-1984 Chevrolet S10, N/A; Fits 1983-1984 Chevrolet S10 Blazer, N/A; Fits 1983-1984 GMC S15, N/A; Fits 1983-1984 GMC S15 Jimmy, N/A; Fits 1979-1983 Buick Riviera, N/A; Fits 1975-1982 Buick Regal, N/A; Fits 1978-1982 Chevrolet El Camino, N/A; Fits 1978-1982 Pontiac Grand Prix, N/A; Fits 1971 Jeep CJ5, N/A; and additional listed applications across Buick, Chevrolet, Oldsmobile, and Pontiac models.

What It Helps Address

• Cracked or hardened coolant bypass hose material
• Coolant leaks from aged curved radiator hose routing
• Improper hose fit from incorrect diameter or shape
• Cooling system service on classic GM and Jeep vehicles
• Replacement needs for vehicles with factory-style curved hose routing

Installation Notes and Tips

Verify the hose path, end diameters, and routing before installation. This hose uses a 19/32 in. inside diameter at both ends and is intended for applications that match the listed curved routing. Confirm vehicle-specific notes such as California emissions or no-air-conditioning requirements where shown in the fitment data, including certain Buick, Chevrolet, and Jeep listings.

Quality Assurance

Dayco manufactures this hose to SAE J20R4 Class D-1 and SAE J1684 Type EC standards for cooling-system hose service. The EPDM construction and application-specific shape support consistent replacement fitment for the listed vehicles, including Buick LeSabre, Chevrolet S10, and Pontiac Grand Prix applications.