How to Remove the Heater Core From a Honda Passportby Daniel Valladares
If the heater core in your Honda Passport is no longer functioning, you may notice that your vehicle does not blow out warm air from the A/C, or you may notice that the floor of your vehicle is always wet. A faulty heater core will leak out into the interior compartment, so it is important that you remove and replace it quickly. Although it is a fairly straightforward process, it can take well over three hours to remove your Passport's heater core.
Open the Passport's hood and disconnect the negative battery terminal with a socket wrench.
Place a drain pan underneath the radiator drain plug. Loosen the drain plug with a socket wrench. Let all of the coolant flow out into the drain pan and re-tighten the plug.
Disconnect the air conditioning evaporator lines at the rear of the engine compartment.
Use a Phillips screwdriver to disconnect the heater-control valve, and rotate the valve so that it is completely open.
Pull out the two heater hoses at the rear of the engine compartment to disconnect them from the heater core.
Uninstall the mounting nut located on the heater control valve bracket, using a socket wrench.
Open the driver's side door and remove the five screws securing the instrument panel into the vehicle -- there are three screws holding the instrument panel into the vehicle and two screws holding the dash panel over the instrument panel. Remove the two upper screws first, and then pull off the dash panel.
Disconnect the electrical connector from the instrument panel and remove it from the Passport.
Disconnect the blower motor's electrical connector and remove the two bolts securing the blower motor. Pull the blower motor out of the Passport.
Unplug the heater-controlling cable from the A/C unit and pry off the expansion valve cover with a flat-head screwdriver.
Remove the four screws securing the heater core into the vehicle. Disconnect the electrical connector from the heater core and pull it out of the vehicle. Installation is the reverse of removal. Do not forget to add the liquid from the drain pan back into the radiator or to reconnect the battery.