Four Seasons 98788 HVAC Heater Core

Four Seasons 98788 Heater Core Overview

The Four Seasons 98788 heater core is a copper/brass HVAC heater core built for direct replacement in select GMC truck applications. It is specified for 1964-1966 GMC G1000 Series and GMC G1500 models with a standard heater and no air conditioning.

Four Seasons Heater Core line parts are focused on replacement fit and OE-style construction for heating system service. This heater core meets or exceeds OEM requirements and uses a copper/brass core material for traditional heat transfer performance.

Key Features

• Part number: 98788
• Copper/brass heater core construction
• Core dimensions: 7-1/8 in. height, 6-1/2 in. width, 2-1/2 in. depth
• Tube sizes: 0.750 in. and 0.625 in.
• Meets or exceeds OEM specifications
• Fits 1964-1966 GMC G1000 Series, N/A, with standard heater and no A/C
• Fits 1964-1966 GMC G1500, N/A, with standard heater and no A/C

Detailed Description

The Four Seasons 98788 heater core is a copper/brass HVAC heater core for restoring cabin heat in classic GMC applications. It is sized at 7-1/8 inches long, 6-1/2 inches wide, and 2-1/2 inches thick, with fixed pipe positioning and tube diameters of 0.750 inch and 0.625 inch. This part cross-references Gates 2440 for the same application.

Use this heater core when servicing the heating system in a 1964-1966 GMC G1000 Series or GMC G1500 equipped with a standard heater and without air conditioning. The Four Seasons 98788 is a direct-fit replacement for vehicles that require the listed core dimensions and tube configuration.

What It Helps Fix

• Weak or inconsistent cabin heat
• Coolant seepage from a worn heater core
• Restricted heat transfer inside the HVAC system
• Heater performance loss in standard-heater GMC trucks
• Replacement needs during HVAC system repair on classic GMC G1000 Series and G1500 models

Installation Notes and Tips

Verify heater box space, tube orientation, and core dimensions before installation. This heater core is listed for vehicles with a standard heater and no air conditioning, so confirm the HVAC configuration on the vehicle before ordering. Match the existing tube sizes and mounting layout to the original unit for proper fitment.

Quality Assurance

Four Seasons lists this heater core as meeting or exceeding OEM requirements. The copper/brass construction supports traditional heater core service in older GMC HVAC systems.