Four Seasons 98505 HVAC Heater Core

Heater Core for GM A-Body HVAC Service

The Four Seasons 98505 heater core is an aluminum HVAC replacement built for vehicles equipped with air conditioning. With a compact 7-1/4 in. height, 6 in. width, and 1-1/4 in. thickness, it matches the dimensions needed for select GM applications including Chevrolet Monte Carlo, Buick Regal, and Pontiac Grand Prix models.

Four Seasons Heater Core line parts are focused on direct-fit HVAC service for aging cooling and heating systems. This aluminum heater core meets or exceeds OEM requirements and uses tube sizes of 0.625 in. and 0.750 in. for the specified application.

Key Features

• Four Seasons part number 98505
• Aluminum heater core construction
• Core dimensions: 7-1/4 in. x 6 in. x 1-1/4 in.
• Meets or exceeds OEM specifications
• Designed for vehicles equipped with air conditioning
• Tube sizes: 0.625 in. and 0.750 in.
• Direct replacement style for HVAC heater core service

Detailed Description

This HVAC heater core is intended for select GM mid-size and G-body platforms, including 1978-1988 Chevrolet Monte Carlo, 1978-1987 Buick Regal, 1978-1987 Chevrolet El Camino, and 1978-1987 Pontiac Grand Prix. It also covers additional applications such as Chevrolet Malibu, Oldsmobile Cutlass, Cutlass Salon, Cutlass Cruiser, Cutlass Calais, Pontiac Bonneville, Grand LeMans, LeMans, Grand Am, Buick Century, and Oldsmobile Custom Cruiser across the listed model years. If you are replacing a leaking or restricted heater core in a classic GM HVAC system, Four Seasons 98505 provides the correct aluminum core format for the application.

This part cross-references Dorman - HELP 94505 for the same application.

What This Part Helps Fix

• Loss of cabin heat from a leaking or clogged heater core
• Coolant odor inside the passenger compartment
• Fogging or film on the inside of the windshield caused by heater core seepage
• Uneven or weak heat output from the HVAC system
• Cooling system contamination related to internal heater core failure

Installation Notes and Tips

• Verify the vehicle is equipped with air conditioning before ordering.
• Confirm core dimensions and tube sizes against the original unit before installation.
• Inspect heater hoses, clamps, and coolant condition during replacement.
• Flush the cooling system if contamination or debris is present.
• Check for leaks and proper heater operation after installation.

Quality Assurance

Four Seasons 98505 is listed as meeting or exceeding OEM specifications for the stated application. The aluminum construction supports standard HVAC replacement service on the covered Chevrolet, Buick, Oldsmobile, and Pontiac models.