Dayco 88412 HVAC Heater Hose

Dayco 88412 Small I.D. Heater Hose

Dayco 88412 is a branched HVAC heater hose built for vehicles that need a small inside diameter coolant hose with multiple connection points. Made from EPDM and finished in black, it is specified for heater outlet, heater-to-tank, radiator-to-throttle-body, heater-to-thermostat, thermostat-to-heater, and auxiliary heater outlet applications across a wide range of GM trucks and SUVs.

Key Features

• EPDM construction for heater hose service
• Black finish for a factory-style appearance
• Branched hose design for multi-port routing
• End inside diameters: 23/32, 1, and 19/32
• End outside diameters: 1 1/16, 1 11/32, and 1
• Meets SAE J20R3 Class D-1 and SAE J1684 Type EC specifications
• Dayco 88412 cross-references ACDelco 18221L and Gates 22554 for the same application

Product Details

Dayco’s Small I.D. Heater Hose line focuses on replacement hoses for compact coolant routing where molded branches and precise diameters matter. Part number 88412 is a branched hose with a 12-inch trunk height, built in EPDM to handle heater circuit service in demanding underhood conditions. It is a direct-fit style replacement for many Chevrolet Silverado, GMC Sierra, Cadillac Escalade, Tahoe, Yukon, and related GM applications, including 1999-2014 Silverado 1500 and Sierra 1500 heater outlet setups and 2000-2014 Tahoe and Yukon heater outlet configurations. If you are replacing a worn heater hose on a Chevrolet Silverado or GMC Sierra, Dayco 88412 provides the correct branched routing and small I.D. sizing needed for these applications.

Common Repair Uses

• Cracked or softened heater hose sections
• Coolant seepage at branched hose connections
• Restricted heater flow from aged rubber hose
• Incorrect routing after prior hose replacement
• Loss of cabin heat caused by leaking heater circuit plumbing

Installation Notes

Verify the vehicle’s year, make, model, and hose position before installation. Match the branched layout and all three connection diameters to the original hose, especially on GM truck and SUV heater outlet applications. Inspect adjoining clamps, fittings, and coolant passages for wear or corrosion before installing Dayco 88412. Proper coolant refill and system bleeding are important after hose replacement.

Quality Assurance

Dayco 88412 is built to SAE J20R3 Class D-1 and SAE J1684 Type EC specifications for heater hose service. The EPDM construction and branched configuration support OE-style replacement needs for GM applications, including Chevrolet Silverado, GMC Sierra, Cadillac Escalade, and related models.