How to Replace a Heater Core in a 1995 Chevy Lumina

The heater core in your 1995 Chevy Lumina is a small heat exchanger located under the dash that carries hot coolant from the engine into the passenger compartment. Air blown over the heater core, by the blower,motor, absorbs the heat from the coolant and passes that heat into the passenger compartment. Common failures of the heater core in the Lumina are associated with leaks in the plastic transfer tubes that pass through the firewall. The replacement heater cores are equipped with aluminum transfer tubes that are less prone to leakage.

Remove the negative battery cable and the plastic engine cover. Place a drain pan under the car, below the heater hose connections. Squeeze the tabs on the heater hose clamps with a pair of pliers and slide the clamps backwards onto the hoses. Twist the hoses to break them loose and pull them off the heater core nipples.

Remove the lower sound insulation panels under both sides of the dash using 7 mm and 8 mm sockets and a ratchet. Remove the lower center console, if equipped, and the lower air ducts from the bottom of the heater core cover.

Remove the eight 7 mm screws that attach the heater core cover to the evaporator case and slide the cover down and forward to remove it. The two screws along the back of the cover, between the cover and the firewall, are especially challenging to remove and will require the use of a universal joint and extension along with the 7 mm socket and ratchet.

Remove the screw that attaches the heater core bracket and slide the heater core out of the evaporator case. Rotate the inlet and outlet tubes on the new core to match the old core, and slip the new core into place, securing it with the bracket and screw.

Reinstall the heater core cover, air duct and console. Reinstall the lower sound insulator panels. Slip the heater hoses onto the inlet and outlet tubes and slide the hose clamps into place. Refill the engine with coolant to replace the coolant that was lost during heater core removal.