Dayco 70873 HVAC Heater Hose - Heater To Engine or Heater To Pipe

Curved Heater Hose for Select Applications

Dayco 70873 is a curved HVAC heater hose built from EPDM rubber for coolant transfer in heater-to-engine and heater-to-pipe routing. With 5/8-inch inside diameter ends and a black finish, it is a direct-fit style replacement for select Kia Sorento, Toyota Tundra, and Mercury Grand Marquis applications.

The Dayco Curved Radiator Hose line focuses on formed hose routing for vehicles that need a specific bend to maintain proper coolant flow and fitment. Part number 70873 follows that approach with a single I.D. hose design and SAE J20R4 Class D-1 / SAE J1684 Type EC compliance.

• EPDM construction for coolant system use
• 5/8-inch inside diameter at both ends
• Curved hose profile for formed routing
• Black finish for OE-style appearance
• Single I.D. hose design
• Meets SAE J20R4 Class D-1 and SAE J1684 Type EC specifications

Detailed Product Overview

Dayco 70873 is a curved heater hose intended for vehicles that require a formed coolant hose between the heater circuit and the engine or pipe connection. It is listed for 2003-2006 Kia Sorento heater to engine, 2000-2006 Toyota Tundra heater to engine, and 1988 Mercury Grand Marquis heater to pipe with w/o Auto Temp. Control notes. This part cross-references Gates 21257 for the same application.

For buyers searching for a 2000-2006 Toyota Tundra heater hose, a 2003-2006 Kia Sorento heater to engine hose, or a 1988 Mercury Grand Marquis heater to pipe hose, Dayco 70873 provides the specified curved routing and 5/8-inch sizing needed for proper connection.

What This Hose Helps Address

• Coolant leaks from a cracked or aged heater hose
• Restricted coolant transfer through a deteriorated hose
• Improper routing when a straight hose does not match the factory bend
• Softening, swelling, or splitting in an EPDM hose exposed to heat and coolant
• Fitment issues on heater-to-engine or heater-to-pipe connections

Installation Notes and Tips

Verify the hose routing, end diameters, and application notes before installation. This hose does not include a heat shield or protective sleeve, so inspect nearby components for abrasion or heat exposure during service. Confirm the vehicle’s heater circuit configuration, especially on the 1988 Mercury Grand Marquis with w/o Auto Temp. Control notes, before replacing the original hose.

Quality Assurance

Dayco manufactures this hose to SAE J20R4 Class D-1 and SAE J1684 Type EC specifications for heater and coolant hose applications. The formed EPDM construction and application-specific bend support consistent replacement fitment for the listed Kia Sorento, Toyota Tundra, and Mercury Grand Marquis vehicles.