Dayco 70621 Radiator Coolant Hose - Upper

Dayco Curved Radiator Hose 70621

Dayco 70621 is a curved radiator coolant hose for upper cooling-system routing on a range of classic Buick, Cadillac, Oldsmobile, and Pontiac applications. Built from EPDM rubber and formed as a single I.D. hose, it provides a direct-fit replacement for vehicles that need a 1 1/2-inch inside diameter at both ends.

Key Features

• EPDM construction for coolant-hose service
• Black finish for a factory-style appearance
• 1 1/2 in. inside diameter at both ends
• Single I.D. hose design for upper radiator routing
• Meets SAE J20R4 Class D-1 and SAE J1684 Type EC specifications
• Curved profile for applications requiring formed hose routing

Product Details

The Dayco Curved Radiator Hose line is built for vehicles that need a shaped coolant hose rather than a straight universal section. Part number 70621 uses EPDM material, which is commonly specified for radiator and heater hose service because it handles hot coolant exposure and repeated temperature cycling. The hose is black, measures 1 1/2 inches inside diameter at each end, and follows a curved form with a 27 1/2-inch trunk height for upper hose routing.

This Dayco 70621 radiator coolant hose is listed for upper-position applications on 1968-1976 Cadillac DeVille, 1968-1976 Cadillac Eldorado, 1968-1976 Cadillac Fleetwood, 1970-1976 Cadillac Commercial Chassis, 1975-1977 Buick Century, 1975-1977 Buick Regal, and other classic GM platforms. It also cross-references Gates 20683 and 21007 for the same application.

What It Helps Fix

• Cracked or hardened upper radiator hose material
• Coolant leaks at the hose body from age-related wear
• Incorrect hose shape that causes routing stress
• Restricted coolant flow from a deteriorated hose interior
• Fitment issues on upper hose replacements for classic GM vehicles

Installation Notes

Verify the hose shape, end diameter, and upper-position routing before installation. Confirm whether the vehicle is equipped with air conditioning where noted in the fitment data, especially on Cadillac, Buick Skylark, and Oldsmobile Omega applications. Inspect hose clamps, radiator necks, and thermostat housing connections for corrosion or damage before installing the new hose.

Fits 1968-1976 Cadillac DeVille, upper; fits 1968-1976 Cadillac Eldorado, upper; fits 1968-1976 Cadillac Fleetwood, upper; fits 1970-1976 Cadillac Commercial Chassis, upper; fits 1975-1977 Buick Century, upper; fits 1975-1977 Buick Regal, upper; fits 1977-1979 Buick Skylark, upper; fits 1976-1978 Buick LeSabre, upper; fits 1977-1978 Oldsmobile Delta 88, upper; fits 1977-1979 Oldsmobile Omega, upper; fits 1977-1979 Pontiac Phoenix, upper.

Quality Assurance

Dayco manufactures this hose to SAE J20R4 Class D-1 and SAE J1684 Type EC specifications for radiator coolant hose service. The part is built for direct replacement use in supported upper radiator applications across Buick, Cadillac, Oldsmobile, and Pontiac vehicles.