Dayco 72900 Radiator Coolant Hose - Upper

Curved Upper Radiator Hose for Mazda Cooling Systems

Dayco Curved Radiator Hose 72900 is a black EPDM upper coolant hose built for select Mazda applications. It is shaped as a curved radiator hose with 1 1/4-inch inside diameters at both ends to support a direct coolant connection in the upper cooling circuit.

Compatible With 2014-2018 Mazda 3, upper; 2014-2018 Mazda 3 Sport, upper; and 2014-2018 Mazda 6, upper. This Dayco radiator coolant hose is a fitment-based replacement for drivers searching for a 2014-2018 Mazda 3 upper radiator hose or a 2014-2018 Mazda 6 upper coolant hose.

Key Features

• Dayco Curved Radiator Hose, part number 72900
• EPDM construction for coolant-system service
• Black finish for OE-style appearance
• Single I.D. hose design
• 1 1/4-inch inside diameter at both ends
• Built to SAE J20R4 Class D-1 and SAE J1684 Type EC specifications
• Fits upper radiator hose applications on select Mazda models

Product Details

Dayco 72900 is a curved radiator hose made from EPDM, a material commonly used in cooling-system hose applications for its resistance to heat and coolant exposure. The hose measures 16 1/2 inches in trunk height and uses matching 1 1/4-inch end diameters, with 1 21/32-inch outside diameters at both ends. Its curved profile supports the routing required in the upper radiator hose position on the Mazda 3, Mazda 3 Sport, and Mazda 6 from 2014 through 2018. Dayco 72900 is a practical replacement choice when servicing the upper coolant path on these vehicles.

Dayco’s Curved Radiator Hose line focuses on formed hose routing for specific cooling-system layouts, helping match the original hose shape and connection points used in the vehicle’s upper radiator circuit.

What It Helps Fix

• Cracked or split upper radiator hose
• Coolant leaks at the hose connection points
• Softened or swollen hose material from heat and age
• Restricted coolant flow caused by hose deterioration
• Incorrect hose routing in the upper cooling system

Installation Notes and Tips

Verify hose routing, end diameters, and upper-position fitment before installation. Inspect the radiator neck and engine-side connection surfaces for wear, corrosion, or residue before installing the new hose. Use proper coolant service procedures and confirm the hose is seated fully at both ends after the cooling system is refilled and bled.

Quality Assurance

This hose is manufactured to SAE J20R4 Class D-1 and SAE J1684 Type EC standards for radiator coolant hose applications. Dayco 72900 is engineered for the listed Mazda fitments and cooling-system service requirements.