Dayco 88406 HVAC Heater Hose - Heater Inlet

Dayco Small I.D. Heater Hose 88406

Dayco 88406 is a Small I.D. Heater Hose built for heater inlet service on select GM minivans. It uses EPDM construction with a black finish and a protective sleeve to support heat and abrasion resistance in underhood HVAC routing.

This heater hose is a direct-fit option for 1997-2000 Oldsmobile Silhouette, 1999-2000 Pontiac Montana, and 1997-1999 Pontiac Trans Sport at the heater inlet, for vehicles without an auxiliary heater. The Dayco Small I.D. Heater Hose line focuses on OE-style hose routing and sizing for replacement applications that require a precise inside diameter.

Key Features

• EPDM heater hose construction for HVAC coolant transfer
• Black hose finish for a factory-style appearance
• 23/32 in. inside diameter at both ends
• Single I.D. hose design for heater inlet routing
• Protective sleeve included; heat shield not included
• Built to SAE J20R3 Class D-1 and SAE J1684 Type EC specifications

Detailed Description

Dayco 88406 is engineered as a small inside diameter heater hose for the heater inlet side of the HVAC system. The EPDM material is selected for coolant hose service, while the protective sleeve adds an extra layer where the hose runs near heat or abrasion points. With matching 23/32-inch inside diameters on both ends, this hose supports accurate replacement of the original routing on the listed Oldsmobile Silhouette, Pontiac Montana, and Pontiac Trans Sport applications. This part cross-references Duralast D88406 and General Motors 10239238 for the same application.

What It Helps Fix

• Cracked or hardened heater inlet hose material
• Coolant seepage at the HVAC hose connection
• Restricted heater coolant flow from a deteriorated hose
• Heat-related wear where the hose passes near engine components
• Incorrect replacement hose sizing on small I.D. heater circuits

Installation Notes and Tips

Verify the vehicle uses the heater inlet hose position and does not have an auxiliary heater before installation. Match the 23/32-inch inside diameter and route the hose to follow the original path so the protective sleeve stays in the intended location. Confirm clamp condition and inspect adjoining heater pipes before final assembly.

Quality Assurance

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