View Full Version : '65 heater box rebuild

05-16-2017, 04:43 PM
My heater box was in bad shape; the clue was the 'cardboard' defroster plenum decomposing, so I decided to pull the whole works and see what I could do. I found out the previous owner had been in there before me- I'm guessing he replaced the heater core, as it was like new, but jeez, what a hack job he did!

The end of the fiberglass box was missing a big chunk, and the fresh air bellows that connects to the cowl intake was made out of a piece of thin plastic that was formed into a circle & screwed to both the box & the cowl.

So I ordered a new plastic plenum, a box seal kit, new defroster tubes, a new 2-speed motor and a new bellows, along with a small fiberglass repair kit. I used the plastic sheet from the homemade bellows to build a form for the end of the box, riveted in place, and laid up the 'glass to create a new end for the missing chunk.
Good as new! Here's some before, during & after photos:

05-16-2017, 05:00 PM
Looking good. We like those kinda project "picture posts". I'm pretty sure most of us at one time or another have had to do some kind of repair work on our heaters. I know I did.
Cardboard boxes just don't hold up when your lady put's her feet on them while riding in the middle.

05-16-2017, 10:31 PM
This is interesting. I had a heater box in my storage and just pulled it out. It also has a cracked case so I have the fiberglas out to fix it. I am going to order the new motor and sell it on ebay of craigslist. Good job on yours and thanks for the pics. Larry

05-17-2017, 02:55 AM
Good as new! Here's some before, during & after photos:

Hello, Beer Belly.

Good job on the re-build.


What is the yellow sticker that is on top?

I do think that it is interesting how Ford chose to make the heater box out of fiberglass. I wonder why they did not use metal or plastic. The fiberglass does give the Falcon something to have in common with a Corvette. :p

Thanks, Dennis.

05-17-2017, 05:36 AM
Dennis, that's a printed factory code, probably a date code or part number. I masked it off before I painted the case.

Fiberglass and cardboard does seem like an odd combination for a heater. Seems like all plastic would have been a better idea.

05-17-2017, 11:39 AM
Good repair!

I have a lot of spare heater box parts if anyone needs something. They're not anything I would sell individually, but figured as many Falcons it is I touch (it seems) I ought not throw any of it away. I should, like Larry, collect it all into one place and see how many I could build with what I have. That said, I think Mustang vendors sell complete boxes (made of plastic, I think) since the 64-66 heaters are nearly identical IIRC.