How to change heater core

-HEATER CORE
Removal
Remove the HVAC module assembly. Refer to A/C-HEATER MODULE.
Remove the heater core case cover screws and cover.
Remove the heater core bracket screws and brackets.
Remove the heater core from the HVAC module assembly.

A/C-HEATER MODULE
Removal & Installation
Disconnect negative battery cable. Drain cooling system. Discharge A/C system, using approved refrigerant recovery/recycling equipment. Raise vehicle. Disconnect evaporator lines from evaporator. Remove heater hoses at heater core. Remove A/C-heater module mounting bolts.
Lower vehicle. Remove instrument panel and instrument panel tie bar. See INSTRUMENT PANEL. Remove floor outlet duct. Disconnect wiring harness from module, blower motor and blower motor resistor. Remove A/C-heater module. See Fig. 1.
To install, reverse removal procedure. Fill cooling system, and check for leaks. Evacuate, charge, and leak test system.