Dayco 71678 HVAC Heater Hose - Valve To Pipe

Curved Heater Hose for OE-Style Cooling Service

Dayco 71678 is a curved radiator hose built from EPDM rubber for heater and coolant routing where a 5/8 in. inside diameter is required at both ends. This black single I.D. hose follows the curved path needed in select Ford, Mercury, Lincoln, and Acura applications, including 2007-2008 Acura TL, valve to pipe.

Key Features

• EPDM construction for coolant and heater hose service
• Black finish for a clean OE-style appearance
• 5/8 in. inside diameter at both ends
• Single I.D. hose design for curved routing
• Built to SAE J20R4 Class D-1 and SAE J1684 Type EC specifications
• Dayco 71678 curved radiator hose for select HVAC hose applications

Product Details

Dayco’s Curved Radiator Hose line focuses on formed hose routing for vehicles that need a precise bend rather than a straight universal hose. Part number 71678 uses EPDM material to handle heater and coolant flow in a black, molded-style profile with matching 5/8 in. ends. It is listed for 2007-2008 Acura TL, valve to pipe, and also appears in fitment for 1991-1995 Ford Taurus, 1991-1995 Mercury Sable, and 1991-1994 Lincoln Continental. This part cross-references Motorcraft KM1918 for the same application.

Common Problems It Can Address

• Cracked or hardened heater hose material
• Coolant seepage at a formed hose section
• Restricted flow from a collapsed or aged hose
• Incorrect hose shape during HVAC hose replacement
• Service needs on vehicles requiring a 5/8 in. curved hose

Installation Notes and Tips

Verify the hose route, end diameters, and position before installation. This hose is listed for valve-to-pipe use on the 2007-2008 Acura TL and for N/A-position applications on the Ford Taurus, Mercury Sable, and Lincoln Continental fitments shown. Inspect adjoining pipes, clamps, and sealing surfaces for wear before installing Dayco 71678. Confirm the hose follows the original curved routing to avoid kinks or tension at the connection points.

Quality Assurance

Dayco 71678 is manufactured to SAE J20R4 Class D-1 and SAE J1684 Type EC requirements, supporting specification-based replacement for select heater and radiator hose applications.