what glue/cement would work to repair a damaged piece on my heater box?

 

If you're talking about the box on the engine side of the firewall, it's fiberglass. Get a resin and mat kit. Be sure to completely clean the area to be repaired with a good precleaner solvent and rough it up with sandpaper first.

 

The fiberglass heater box in my Olds was broken and I repaired it with 2 part epoxy. Of course, there wasn't a hole in my box, part of the plenum just broke off where it met the AC condensor box. All I did was rough up the two mating surfaces with sandpaper, cleaned it really good and epoxyed them together. I used C clamps to hold the two pieces where I wanted them while it was curing. It worked great.

If there is an actual hole in your heater box and you don't have the piece that was punched out of it then you will want to use a resin and mat kit.

 

actually, it is just a couple parts of the plenum that broke off, I'll try the epoxy
and fix it up

thanks

 

I went with a friend to a fairly large junkyard near where I live. in the rows of Oldsmobiles,
I found a cutlass salon like mine, with a good box in it. however to remove it, I would have to remove the inner fender,and a damaged fender to get at it. I also found a '78-80 (not sure of exact year) malibu 4 door, with the front clip completely gone. would the heater box from the malibu fit My Olds?
I can get either one for $ 50

but, I'm gonna try and fix mine first,and see if I can save it.otherwise, I'll go buy another one