Dayco 70734 Radiator Coolant Hose - Upper

Dayco Curved Radiator Hose 70734

Dayco 70734 is a curved radiator coolant hose built for upper cooling-system routing on select Chevrolet and GMC vans. Made from EPDM rubber with a black finish and 1 1/2-inch inside diameter at both ends, it is specified for vehicles that need a single I.D. hose in the upper radiator position.

Key Features

• EPDM construction for coolant-hose service
• Black curved radiator hose profile for upper routing
• 1 1/2-inch inside diameter at both ends
• Single I.D. hose design
• Meets SAE J20R4 Class D-1 and SAE J1684 Type EC specifications
• No heat shield and no protective sleeve

Product Details

The Dayco Curved Radiator Hose line is built for direct-fit cooling-system service where a formed hose is required to follow the factory routing. Part number 70734 is an upper radiator coolant hose for Chevrolet G10, G20, and G30 vans, plus GMC G15, G25, G35, G1500, G2500, and G3500 applications listed in the fitment data. This hose is also cross-referenced to common aftermarket and OE numbers, including Gates 20840 and CARQUEST 20840 for the same application.

Dayco 70734 is a practical replacement when servicing aging upper coolant hoses on classic Chevrolet G10/G20/G30 and GMC G15/G25/G35 van platforms. The curved shape supports the original hose path, while the EPDM material is selected for radiator coolant service and temperature exposure typical of these vehicles.

Vehicle Fitment

• Fits 1976-1979 Chevrolet G10, Upper; compatible with vehicles containing air conditioning and vehicles without air conditioning.
• Fits 1975-1979 Chevrolet G20, Upper; compatible with vehicles containing air conditioning and vehicles without air conditioning.
• Fits 1975-1979 Chevrolet G30, Upper; compatible with vehicles containing air conditioning and vehicles without air conditioning.
• Fits 1979 GMC G1500, Upper.
• Fits 1979 GMC G2500, Upper.
• Fits 1979 GMC G3500, Upper.
• Fits 1976-1978 GMC G15, Upper; compatible with vehicles containing air conditioning and vehicles without air conditioning.
• Fits 1976-1978 GMC G25, Upper; compatible with vehicles containing air conditioning and vehicles without air conditioning.
• Fits 1976-1978 GMC G35, Upper; compatible with vehicles containing air conditioning and vehicles without air conditioning.
• Fits 1975-1976 Chevrolet G10, Upper.
• Fits 1975-1976 Chevrolet G20, Upper.
• Fits 1975-1976 Chevrolet G30, Upper.
• Fits 1975 GMC G15, Upper.
• Fits 1975 GMC G25, Upper.
• Fits 1975 GMC G35, Upper.
• Fits 1972-1974 GMC G15/G1500 Van, Upper.
• Fits 1972-1974 GMC G25/G2500 Van, Upper.
• Fits 1972-1974 GMC G35/G3500 Van, Upper.

Common Issues This Hose Can Address

• Cracked or hardened upper radiator hose material
• Coolant seepage at the hose body or ends
• Collapsed or softened hose sections under heat and pressure
• Incorrect hose shape after prior repairs or replacements
• Cooling-system service on Chevrolet G10/G20/G30 and GMC G15/G25/G35 vans

Installation Notes

Verify the upper hose routing, end diameters, and vehicle configuration before installation. This hose uses a 1 1/2-inch inside diameter at both ends and is intended for upper radiator placement on the listed Chevrolet and GMC applications. Inspect hose clamps, radiator necks, and thermostat housing connections for wear before installing the new hose.

Quality Assurance

Dayco manufactures this hose to SAE J20R4 Class D-1 and SAE J1684 Type EC specifications for radiator coolant hose service. The EPDM construction and formed design support consistent fitment on the listed Chevrolet and GMC van applications.