73 nova hatchback heater core how to remove?

We are trying to figure out how to replace the heater core in a 73 nova hatchback. There is a two part cover over it and we have no idea how to get it off and how to replace the heater core.. We never had a problem with our duster or our barracudas nothing like this.. If any person can tell us why the two part cover will not come off we would be greatfull. We have removed all the bolts that we could see. Do we need to remove the side fender to get to something that is holding onto the cover to the heater core? Looks like a stud has been place thru to the inside of the car.... Boy friend is trying to work on it and is about to give up... He has worked on my other cars replacing the heater core but the nova has the cover that will not come off... Any help would be wonderful... Thanks, Kay

I changed one on my 74 which should be the same. It was a while ago but I know I did not remove the fender. You need to drop the heater box from inside the passenger compartment. First pull out the glove box and remove all the nuts on the engine compartment side. One is tucked away tight in between the inner and outer fender panels. On other cars I have removed the bolts that attach the inner and outer fender panels to allow me to pry them apart for a little more room, but I don't think I had to do this on my Nova.

If all the nuts are off then it's just a matter of loosening it up. You can try lightly tapping on the studs and pulling on the box from inside the car. The studs stay attached to the heater box. Do not detach the operating cables, just lay the box on the car floor face up. Pay attention to how the little clip(s) hold the core in place, so when you install the new one it won't be rattling around as you drive. Clean the mounting surfaces and use a bead of gasket sealant when reinstalling. You didn't say if your car has AC. Mine doesn't.

I hope this helps and welcome aboard! :wave: