Call an AC expert to get your refrigerant out and back. Take the battery cable off the terminal that's connected to the ground. Drain the cooling system. Disconnect the heater hoses from the firewall. Get rid of the connection on the evaporator that brings air conditioning into the car. Pull out the temperature control cable from the heater unit; cars with automatic heating controls have no temperature control cable. Tear out the center console, instrument panel, and support place that holds the panel from behind. Remove the blower motor housing. Take off the heater housing fasteners, raise it from the vehicle, and keep shop towels on the floor to catch any spilled coolant until you can wipe it away; clean coolant off painted surfaces right away using cold water. Opening the heater heating core asks you to take off both parts of the heater housing, unscrew all fasteners, and then split the housing in half to get at the core. Place the new heater core where it fits into the housing, making sure the seal foam belongs where it should, then fix the cover if needed. Put all heater housing parts back together, after which you can reinstall your heater system in the car. Reinstall any heater ducts you took off or separated. Reinstall and position these three parts: the sturdy support beam, the info control system, and the center compartment. If you took out the air bag command block, put it back now. Install the temperature control cable. Place both heater hoses and refrigerant lines at the firewall, but swap out any old, cracked hose ends with new ones. Reconnect the power supply to the car and add proper cooling fluid to the coolant system. Before driving, turn on the car and check for leaks from the heater controls.