How do I Change a Heater Core on a '68 GMC Truck?
- 1). Pop the hood. Put the drain pan under the firewall where the heater core lines connect to the heater core. Remove the heater core hose clamps with the flat-head screwdriver, then pull the lines off of the heater core and point them toward the drain pan.
- 2). Move to the passenger side of the dashboard. Take off the temperature door cable at the distributor duct adapter under the passenger side of the dash using your hands. Take the cable off of the temperature door with your hands. Move to the passenger side fender. Loosen the passenger side fender skirt from the inner fender well with the 3/8-inch ratchet and socket set so that you can access the inside of the fender well.
- 3). Unbolt the heater core case from the inner fender well and from the underside of the dash with the 3/8-inch ratchet and socket, as well as a Phillips screwdriver. Pull apart the case and take out the heater core. Install the replacement heater core into the case and bolt it back together with the Phillips screwdriver and the 3/8-inch ratchet and socket. Reinstall the passenger side fender liner with the 3/8-inch ratchet and socket.
- 4). Reinstall the temperature door cable to the temperature door with your hands. Reinstall the heater core lines to the firewall with the flat-head screwdriver. Open the radiator cap and fill the radiator with the 50-50 pre-diluted coolant.