How do you replace a heater core on a Geo Storm?

Answer 1

I am replacing the heater core and followed the skimpy instructions in a paperback manual that were very lacking. There were many steps that were not covered and this might help you if you are doing this job. I had the refrigerant in the air conditioning evacuated, disconnected the refrigerant lines and the air conditioning throttle valve at the firewall, then removed the water hoses to the heater (I am also doing a head removal that made access to the firewall tons easier. That's the easy part! You will need to disconnect the battery, remove the two 10 amp fuses in the fuse box that feed the air bag as well as disconnecting the orange wiring connector at the base of the steering column under the dash. It helped to take the three screws off that hold the square, silver box to the left of the steering column to better access the orange connector. Remove the glove box by gently pulling while twisting the hinge pins at the bottom inside of the box. Remove the center screw near the latch that fastens to the dash. Remove the center console, radio and its housing bracket that connects to the floor, and heater control lever assembly. Now remove two screws under the instrument bezel. Remove the small access covers on the top of the bezel that conceal the other two screws, remove screws and pull out bezel (The instrument cluster remains for now). Remove wiring connectors from bezel that feed the light switches and wipers. Remove screws that hold the instrument cluster, and pull out partially to allow removal of speedometer cable and wire connections after which you will then be able to easily remove the instrument cluster. Remove screws that hold the dash trim strip where the dash meets the windshield. There are screws that hold the ends and one in the center that is concealed by a small access cover. You need something like a small flat hook-like tool to pry the small square plastic screw concealing cover up and back. Now the dash hold down bolts will be exposed to allow their removal. The center fastener is a nut that holds the dash down on a fixed stud. The Dash will eventually need to be pulled up over the stud to clear the stud before the dash will pull away from the firewall. There are some other minor fasteners that hold various parts of the dash to brackets under the dash. Keep wiggling the dash to see where it is hanging up and remove what you need to. Once the dash is loose you simply pull it out. You will have good access to the heating/cooling assembly. Remove the control cables and wiring to the unit. Then remove the six or so nuts that attach the unit to the firewall. Remove the center floor ducting by removing three or four small screws that hold it to the main unit. You will notice a tubular steel strut just behind the dash that runs the width of the interior that supported the dash. It has some sharp tabs welded to it, so be careful. The right side can be loosened by simply removing two bolts to facilitate removal of heater components. I tried to separate, pull, and wiggle the three component parts of the heater unit (right to left: Blower, air conditioning condenser housing, and the main control box that houses the heater core) to remove them. All came loose except for the black box that houses the air conditioner condenser. It would not need to be removed except to provide a path to remove the main box that houses the heater core. It feels very loose but something at the firewall is holding it from behind. I'll try again tomorrow.