Heater core is in front of the passenger under the dash in the "heater box" it contains the AC condenser also. Pull the front seats out for room, pull the center console out and drop the steering column by undoing 2 nuts on the bracket. Undo every 7mm/8mm (mostly) bolt on the dash and gage cluster. (when removing the gage cluster be sure to unplug the switches and SPEEDOMETER CABLE! take dash out and open heater box. Go under the hood and disconnect the coolant hoses from the two studs. Remove the old heater core from the box and replace it. work backwards from there. this is not very detailed but i hope it helps.