Dayco 72317 Radiator Coolant Hose - Upper

Curved Upper Radiator Hose for Mazda 6

Dayco 72317 is a curved radiator coolant hose built for the upper cooling circuit on select Mazda 6 models. It uses EPDM construction with a black finish and a protective sleeve to help manage heat and abrasion in the engine bay.

This Dayco Curved Radiator Hose line focuses on OE-style cooling system replacement parts with application-specific shapes and material choices. For buyers searching for a Mazda 6 upper radiator hose, Dayco 72317 provides the correct curved profile for the listed fitment.

Key Features

• EPDM rubber construction for coolant hose service
• Black finish for a factory-style appearance
• Dual I.D. hose design with 1 3/16 in. end 1 and 1 1/4 in. end 2 inside diameters
• Protective sleeve included for added surface protection
• Built to SAE J20R4 Class D-1 and SAE J1684 Type EC specifications
• Fits 2003-2008 Mazda 6, upper

Detailed Description

Dayco 72317 is a curved radiator coolant hose engineered for the upper radiator connection on 2003-2008 Mazda 6 applications. The EPDM hose material is commonly used in cooling systems for its resistance to heat and coolant exposure, while the curved shape supports a proper routing path in the engine bay. The dual inside diameter design matches the listed connection sizes, and the protective sleeve adds an extra layer where the hose passes near hot or abrasive components. This part cross-references Mazda L321-15-186D for the same application.

Common Cooling System Issues It Can Address

• Cracked or split upper radiator hose
• Coolant seepage at the hose connection points
• Softening, swelling, or deterioration from age and heat
• Improper hose routing caused by a worn or misshaped replacement
• Cooling system service on a Mazda 6 with an upper hose leak

Installation Notes and Tips

Verify the hose routing, end diameters, and upper-position fitment before installation. Inspect the radiator necks, clamps, and nearby components for wear or corrosion, and replace any damaged sealing surfaces before filling the cooling system. After installation, refill and bleed the system according to the vehicle service procedure and check for leaks at operating temperature.

Quality Assurance

Dayco manufactures this hose to meet SAE J20R4 Class D-1 and SAE J1684 Type EC requirements for radiator hose applications. The part number for this application is Dayco 72317.