Dayco 71729 Radiator Coolant Hose - Upper - Engine To Pipe or Upper - Pipe To Engine

Dayco Curved Radiator Hose 71729

The Dayco 71729 curved radiator hose is a dual I.D. coolant hose made from EPDM for use in cooling system routing that requires different inside diameters at each end. Its black construction and curved profile support a clean fit in applications that need a 2 1/4 in. end on one side and a 2 1/2 in. end on the other.

Key Features

• Brand: Dayco Curved Radiator Hose
• Part number: 71729
• Dual I.D. hose with 2 1/4 in. inside diameter at End 1 and 2 1/2 in. inside diameter at End 2
• EPDM rubber construction for coolant service
• Black finish for a factory-style appearance
• Built to SAE J20R4 Class D-1 and SAE J1684 Type EC specifications

Product Details

Dayco 71729 is a radiator coolant hose for vehicles that require a curved hose with mismatched end diameters. The EPDM material is selected for cooling system use, while the dual I.D. design helps match the connection points found in specific radiator and engine coolant routing layouts. This part is a practical choice when replacing a worn or damaged hose on applications such as Honda Civic cooling system service or other vehicle platforms that use the same hose dimensions. The Dayco Curved Radiator Hose line focuses on replacement hoses that follow OE-style routing and sizing, and 71729 reflects that approach with a formed shape and standardized SAE specifications. If you are searching for a Dayco 71729 radiator hose, this part is built for direct coolant transfer in the engine cooling circuit.

This part cross-references Gates 20369 and NAPA 7242 for the same application.

What It Helps Fix

• Coolant leaks caused by cracked or aged hose rubber
• Softening, swelling, or collapse in an old radiator hose
• Improper hose fit at different-size connection points
• Cooling system service needs after hose deterioration
• Loss of coolant flow from a damaged curved hose section

Installation Notes and Tips

Verify the hose end diameters before installation to confirm the 2 1/4 in. and 2 1/2 in. connections match the vehicle routing. Inspect clamps, necks, and adjoining coolant pipes for wear, corrosion, or residue before installing the new hose. After installation, refill the cooling system with the correct coolant and check for leaks at operating temperature. Fits should be confirmed against the vehicle’s original hose shape and connection sizes, especially on Honda Civic cooling system repairs and similar applications.

Quality Assurance

This hose is manufactured to SAE J20R4 Class D-1 and SAE J1684 Type EC requirements for radiator and coolant hose service.