Four Seasons 91487 HVAC Heater Core

Four Seasons Heater Core 91487

The Four Seasons 91487 heater core is a copper/brass HVAC replacement built to match the original heating system layout for select Chevrolet and GMC trucks and SUVs. It is sized for direct replacement service and meets or exceeds OEM requirements for the listed applications.

Key Features

• Copper core material with copper/brass heater core construction
• Core dimensions: 8 in. height, 6-1/4 in. width, 2 in. depth
• Tube sizes: 0.625 in. and 0.750 in.
• Meets or exceeds OEM specifications
• Direct-fit HVAC heater core for listed applications
• Four Seasons heater core 91487 for service replacement use

Product Details

Four Seasons Heater Core 91487 is built for the HVAC system in 1983-1985 Chevrolet S10, 1984-1985 GMC S15, and 1984 Chevrolet S10 Blazer applications. The copper core material and copper/brass style support efficient heat transfer in a compact 8 x 6-1/4 x 2 inch package. This part number 91487 is also referenced by Four Seasons 98487 and cross-references Dorman - Conduct-Tite 91487 for the same application.

For buyers searching for a Chevrolet S10 heater core replacement or a GMC S15 heater core, this unit provides the listed dimensions and tube sizing needed for HVAC service work. It is a practical choice when replacing a leaking, restricted, or heat-limited heater core in the original heating circuit.

Common Issues This Part Can Address

• Loss of cabin heat from a restricted or failing heater core
• Coolant odor inside the vehicle from heater core leakage
• Window fogging caused by HVAC coolant seepage
• Uneven or weak defrost performance tied to poor heater output
• Cooling system contamination from an aging heater core

Installation Notes and Tips

Verify core dimensions, tube sizes, and hose routing before installation. Confirm the vehicle application against the listed fitment for 1983-1985 Chevrolet S10, 1984-1985 GMC S15, and 1984 Chevrolet S10 Blazer. Because adjustable pipe positioning is not included, match the existing HVAC layout before assembly. Flush the cooling system and inspect hoses, clamps, and seals during heater core replacement.

Quality Assurance

Four Seasons identifies this heater core as meeting or exceeding OEM requirements for the specified applications. The copper/brass construction and application-specific sizing support service replacement in the original HVAC system.