Dayco 87787 HVAC Heater Hose - Heater To Pipe (Upper)

Dayco Small I.D. Heater Hose 87787

Dayco 87787 is a Small I.D. Heater Hose built for HVAC heater hose service where a dual inside diameter is required. Made from EPDM with a black finish, it includes a protective sleeve and meets SAE J20R3 Class D-1 and SAE J1684 Type EC specifications for heater hose applications.

This Dayco heater hose is a direct-fit option for select Nissan Frontier and Nissan Xterra models with a heater-to-pipe upper routing. The dual I.D. design helps match the factory connection sizes, with a 5/8-inch inside diameter on one end and a 3/4-inch inside diameter on the other.

Key Features

• Brand: Dayco Small I.D. Heater Hose
• Part number: 87787
• EPDM construction for heater hose service
• Dual I.D. hose design: 5/8 in. x 3/4 in.
• Black hose with protective sleeve
• Meets SAE J20R3 Class D-1 and SAE J1684 Type EC
• Compatible with heater-to-pipe upper routing on select Nissan applications

Product Details

Dayco 87787 is part of the Small I.D. Heater Hose line, a product line focused on heater hose routing that requires a smaller inside diameter and a dual-size connection. For Nissan Frontier and Nissan Xterra applications, this hose supports the upper heater-to-pipe connection and is built to match the dimensional needs of the original routing. The EPDM material is commonly used in coolant and heater hose service, while the protective sleeve adds an extra layer where the hose is exposed to underhood conditions.

This part cross-references Gates 18141 and NAPA 10141 for the same application.

Vehicle Fitment

• Fits 1999-2004 Nissan Frontier, Heater To Pipe (Upper), Small I.D. Heater Hose
• Fits 2000-2004 Nissan Xterra, Heater To Pipe (Upper), Small I.D. Heater Hose

Common Replacement Reasons

• Cracked or hardened heater hose material
• Coolant seepage at the upper heater-to-pipe connection
• Incorrect hose size after prior repair work
• Heat-related hose wear in the engine bay
• Loss of heater circuit integrity on Nissan Frontier or Nissan Xterra models

Installation Notes and Tips

Verify the 5/8-inch and 3/4-inch end sizes before installation and compare the routing to the original hose on the vehicle. Confirm the heater-to-pipe upper position on the Nissan Frontier or Nissan Xterra before removal, and inspect nearby clamps, pipes, and coolant connections for wear or corrosion. Proper hose routing and secure clamp placement help maintain a reliable seal.

Quality Assurance

Dayco manufactures this heater hose to SAE J20R3 Class D-1 and SAE J1684 Type EC specifications, supporting consistent material and dimensional standards for HVAC hose replacement.