Knee deep in this project. Following some instructions I got off here I removed the heater core, dremeled the top off a section of the heater box giving me access to this door...
Wrapped it in some foam I got from HomeDepot. Went back in easy enough. What worries me is when it was all apart you could see ANOTHER flap covered in the same disintegrating foam deeper in the heater box. I think it control the air flow to the defrost or the floor. Can't reach it from here. Maybe from behind the radio? Don't try to salvage the foam cover that goes over the heater core. Impossible to get a clean seal the 2nd time around. Spend the $17 on a new one and thank me later.
