As best as I could tell, it looked like the rest of the heater components needed to come out as well. The interior heater box is held to the firewall with four screws and comes out pretty easily; make sure to disconnect the two wiring plugs. The heater core/blower motor box on the engine side of the firewall is another story. The bottom left screw below the motor is hard to get to between the box and the fenderwell, so prepare for some fun. When you're through with that, you may have to loosen the bolts on the hood hinge to fender mount and pull it forward to actually remove and replace the heater core box. If so, mark where the hinge sits before loosening it so the hood alignment goes back to the way it was.