Anyway I aquired a 91 SS (MT) from a fellow board member. I'm at least the 4th owner of this thing, and the first of the last three to see it run.
Last owner put a used engine it, but didn't time it right after he did the HG's.
So upon getting it to fire, I tried to fill it with coolant.... it took a lot. Low! And behold the amazing leaking frame rail!!
Coolant was running out of the heater core box, down under the carpet, and filling up the frame rail through the drain hole in the floor pan. At least the carpet stayed dry
So anyway - my horror (!) at discovering halfway through that I would need to remove the evap core to get the heater core box out. This is unacceptable.
My success story is that you CAN remove the core box without removing the evap core. You have to take the mounts loose for it, and the fan housing, take loose the receiver/drier mount and the bits holding all the lines from moving in the engine bay, and pop out the grommet for them in the firewall. Then you can pull the evap core with it's housing away from the firewall enough to squeeze the heater core box out, and back in again. It's not really even that hard once you pull the evap core out of the way. A heck of a lot easier than recharging the AC system. Especially being that the 91 is an R12 car.
Anyway - I read on here in another post, and also in the Haynes manual that the core had to be removed. Hopefully pointing out that it doesn't will help someone else.
GD
