Replacement of the heater core is a difficult procedure for the home mechanic involving removal of the entire dashboard console, and many wiring connectors. If you attempt it at home, keep track of the assemblies by taking notes and keeping screws and other hardware in small, marked plastic bags for reassembly. Start by having the refrigerant discharged at a dealer service department or an automotive air conditioning repair facility. Disconnect the cable from the negative terminal of the battery. Drain the cooling system. If the coolant is relatively new, or is in good condition, save it and re-use it. Plug all open fittings of disconnected lines to prevent entry of dirt and moisture into the lines. Loosen the hose clamps holding the heater hoses to the heater core tubes and slide the hoses off the tubes. Prepare towels or rags underneath the ends of the heater hoses to catch spilled coolant. Plug the heater core tubes to prevent spillage. On 2008 and earlier models cut the joint caps at the refrigerant line fittings where they connect to the evaporator at the firewall, then remove the fitting stops and disconnect the refrigerant lines from the evaporator core. Discard the old O-rings and joint caps. On 2009 and later models, remove the bolt holding the refrigerant line fitting to the evaporator core and disconnect the lines. Remove the instrument panel. Disconnect the evaporator drain hose from the heater core. Remove the mounting nuts holding the heating and air conditioning housing, then remove the housing from the vehicle. Remove the screws holding the heater core cover and remove the cover. Remove the heater core pipe bracket screw(s). Slide the heater core out from the HVAC housing. Installation is the reverse of removal, noting the following: Do not use old O-rings for the refrigerant lines; replace with new ones and apply R134a-compatible refrigerant oil to them before installation. Reconnect the battery. Refill the cooling system. Check the operation of all electrical components of the steering column and dash. Have the air conditioning system recharged by the shop that discharged it.
