'90 corrado heater core replacement

I have no idea about the configuration of the foam you removed, so my suggestion may not be feasible. Anyway, maybe you could replace that foam with foam that comes in a spray can - which is available at all Home Depot or Lowes stores. Just a thought.

Just get a new box, otherwise remember whatever type of glue you use it must be able to with stand the heat present inside the box which could be as much as about 180*F

Picked up some aluminum clad insulation tape - it sealed up real nice - will see how it does once I crank on the heater :)

Have the same problem on my 95 GTI VR6 - did the insulation tape work and where did you get it? My box is out of the car waiting to go back in - didn't want to spend the $$$$ at the stealership either.

The bought this tape at Wall-Mart. You can probably get it at any hardware store - I've seen it at Lowes and Home Depot as well. Basicly, it's just sticky tape with an aluminum backing. It comes in a roll and I just used scissors to cut it to shape. I've had it in now for a couple of months and it seems to be working vey well. I pulled off all of the deteriorated foam off of the metal plates and cleaned them up pretty good. Cut the tape to fit and stuck everything back together. I can send you some pics if you like - just let me know. -teD