Dayco 70871 Radiator Coolant Hose - Upper

Dayco Curved Radiator Hose 70871

The Dayco 70871 curved radiator hose is a direct-fit coolant hose for select Ford trucks and SUVs. Built from EPDM rubber, it provides the curved upper hose routing needed for proper coolant flow in classic Ford cooling systems.

Key Features

• EPDM construction for coolant-system durability
• Black finish for a clean OE-style appearance
• Dual I.D. hose with 1 1/2 in. end 1 inside diameter and 1 3/4 in. end 2 inside diameter
• Upper curved radiator hose profile
• Built to SAE J20R4 Class D-1 and SAE J1684 Type EC specifications
• Dayco Curved Radiator Hose line for application-specific cooling system replacement

Detailed Description

Dayco 70871 is a curved radiator coolant hose engineered for upper hose applications on 1977-1979 Ford F-100, F-150, F-250, and F-350 models, plus 1978-1979 Ford Bronco. The dual inside diameter design matches the differing connection sizes required by the cooling system, helping maintain a secure fit at both ends. This part cross-references common aftermarket and OE numbers such as Gates 21045 and Motorcraft KM1021 for the same application. If you are replacing a worn upper radiator hose on a Ford Bronco or Ford F-Series truck, Dayco 70871 provides the correct curved routing and hose sizing for these vehicles.

What It Helps Address

• Cracked or hardened upper radiator hose material
• Coolant leaks at the hose connection points
• Improper hose routing in the engine bay
• Softening or swelling from age and heat exposure
• Loss of cooling-system sealing at the radiator or engine neck

Installation Notes and Tips

Inspect the radiator necks and engine fittings before installation, and replace any damaged clamps or corroded connection surfaces as needed. Verify the hose orientation before tightening so the curved shape follows the original routing on the Ford F-100, F-150, F-250, F-350, or Bronco application. Confirm the end diameters match the vehicle connection sizes before final assembly.

Quality Assurance

Dayco manufactures this hose to meet SAE J20R4 Class D-1 and SAE J1684 Type EC requirements, supporting consistent material and performance standards for cooling system service.