Heater core box help

Discussion in 'The Big Chill' started by StfSocal, May 22, 2019.

  1. Brett Slater

    Brett Slater Super Moderator Staff Member

    It definitely can't hurt.

    I didn't use any but I also don't recall seeing remnants of any.

    I did use little round seals that I got from (I think) Heartbeat City to replace the worn out ones behind the firewall box where the studs slide in from inside.
  2. StfSocal

    StfSocal Well-Known Member

    Ya I looked at the pictures of the box when I first removed it and there is some evidence of sealant of some kind. I'll glue the foam one on and slap it in there this weekend hopefully. I will have to look at the firewall in detail to see if there is anything on there. I don't remember seeing any type of little round seals, but who knows. There aren't any in the kit i got, that's for sure.
    Brett Slater likes this.
  3. Brett Slater

    Brett Slater Super Moderator Staff Member

  4. StfSocal

    StfSocal Well-Known Member

    Thanks Brett!

    Ya it appears the sealing compound is indicated on the blower/air inlet cover. On the AC cars (since the evap box is housed in there) that does require a sealant. On the AC evap box I’m going to be using the strip caulk. I was actually taking about between the heater box under the dash and the firewall, inside the cab. That’s where I found a foam seal that fits in my seal kit.

    Still didn’t see any little round seals in the pictures I took during disassembly. I’ll have to look in my assembly manual.
    Brett Slater likes this.
  5. StfSocal

    StfSocal Well-Known Member

    So it appears that there is no seal between the heater box and the firewall. The firewall pad acts as a seal. So I guess I have to decide it I want a new firewall pad. Seems fine so I might be ok. Don’t really want to have to rip a bunch of stuff out from under the dash.

    As for those stud seals, the AC box in the engine bay shows 4 seals for the 4 studs. However they differ from the ones without AC. So not sure if the ones from that site will work.

    I forgot I need to get some vacuum lines before I mount the box.

    Also need to locate two screws that can mount the distribution duct to the heater box. I don’t seem to have any that will work. The car was missing that piece when I got it.
    Last edited: Nov 16, 2019
  6. Brett Slater

    Brett Slater Super Moderator Staff Member

  7. BennyK81

    BennyK81 Well-Known Member

    Hey Scott, I am in the same process as you are...did put together my Heater Box today...
    There is no separate seal between the heater box and the firewall...just that thick firewall pad...mine fell to pieces when removing it. I will use thick butyl sealing cord from Volkswagen where I have no original seals. Also used this between the cast part with the heater core and the box itself. Seals everything up fine (Part no. akd 49701004r10 Volkswagen. You can get it at every dealership)

    I checked your pics and I am sure you can answer me one question:
    What is the function of the screw where I marked the picture. I had one in there but if I screw it back in there all it does is blocking the flap behind it...maybe you can shed some light...


  8. StfSocal

    StfSocal Well-Known Member

    You know Benny, I got to that same point and couldn't for the life of me figure it out. I think i put a bolt in there and figured out that it hit the door. I haven't installed it yet as I am waiting for a new firewall pad. If you figure it out let me know :D:D

    By the way your box looks great. I debated sanding mine down and hitting it with some clear, but then figured it is tucked up under the dash so screw it lol.
  9. BennyK81

    BennyK81 Well-Known Member

    Thanks...yes I did not paint it it just got a good bath in our bathtub :)

    I did reuse the original heater core. I have pressure tested it 24h with no loss.

    Maybe there's someone else who can help us with the bolt. I figured the door should travel all the way up and down to function properly
  10. BennyK81

    BennyK81 Well-Known Member

    bumpbump bolt?
  11. StfSocal

    StfSocal Well-Known Member

    Anyone have an idea on the bolt circles above in Bennys pic?

    gonna slap mine on the firewall today but won’t be able to access the bolt once I do.


  12. wallypep

    wallypep Silver Level contributor

    I , just restored my heater core box ,wondered about that screw also , came to the conclusion that it stops the door flapper from completely closing , why i do not no ,and checked some other boxes some did have the screw there and some dont , maybe some reason latter on they decided they did not want the door closed all the way for air flow ? maybe somebody on here knows
    Last edited: Jan 12, 2020
  13. StfSocal

    StfSocal Well-Known Member

    Interesting, didn’t think about it preventing the door from fully closing.

    Oh well, I just said screw it (pun intended :D:D) and installed the box. She ain’t coming out now for that lil thing. I’m sure it’ll work fine.

    Feels sooooo good to have that box back in with the new insulation pad and all new internals.

    Thanks to everyone for the help with taking on this project. Couldn’t of completed it with out y’all.
    Brett Slater likes this.
  14. Brett Slater

    Brett Slater Super Moderator Staff Member

    Pictures or it didn't happen. :D:D
  15. StfSocal

    StfSocal Well-Known Member

    :rolleyes: You’ll have to wait :p
  16. Brett Slater

    Brett Slater Super Moderator Staff Member

    I just realized I never posted any from when I did mine.

    20190807_174032.jpg 20190807_201212.jpg 20190807_210537.jpg 20190807_203814.jpg 20190807_202601.jpg 20190807_202539.jpg 20190807_211229.jpg
    StfSocal likes this.
  17. Brett Slater

    Brett Slater Super Moderator Staff Member

    I should note that applying the foam to the back of the door - the part you can't see - absolutely sucked!

    However, it's necessary because that door will flap and you'll hear metal on metal when it engages.
    StfSocal likes this.
  18. StfSocal

    StfSocal Well-Known Member

    Luckily the rubber on the blend door was in good shape for me so i didn't replace it. I did however replace the foam that goes on the defrost door (pics on page 2 of this thread), the hardest part of that was removing the factory staples. I used that same glue that Brett did but also re-used the factory staples. Came out good and seals as it should.

    The vacuum modulators were all operational and held vacuum for at least 30 minutes. The only one i had to replace was the one behind the kick panel that operates the fresh air door. That one sucked to remove with out removing the whole assembly.

    Next step is to attach the AC box to the other side of the fire wall. Then it is safe to say this process is completely done.
  19. BennyK81

    BennyK81 Well-Known Member

    what about your blower motor...i intended to rebuild mine but found out it is welded together....
  20. StfSocal

    StfSocal Well-Known Member

    The AC evap box halves are together with the resistor, evap, and seals installed. I still need to install the POA valve, Expansion valve & bulb, and blower motor. I was trying to think of a way to "test" the factory blower motor as I need to find out if it works. If it does i will just install it and call it a day. If not then I need to find a blower motor for an AC equipped car. I don't want to try and rebuild it if I don't have to.

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