12 Attachment(s)
HVAC Box Removed and Modified to Keep Heat
I finally tackled the project of getting the HVAC box out of my firewall, with my engine still in, so I could modify the box to keep the heater and blower fan, with the AC delete plate showing in the firewall hole.
Two words: It sucked
I don't recommend doing this because it sucks a lot, and it will cause moments of frustration for anyone attempting it.
I ended up just taking the entire dash completely out of the car. It sucks reaching under and around the dash and there is little room to work with the dash anywhere near the firewall.
Pay particular attention to post #23 on this thread. There is one evil screw (they're all evil on this project) that holds the center vent box onto the firewall. Don't forget about this, or you will be buying some plastic weld glue. Ask me how I know. Also, be sure to connect the two boxes (the middle one at the center of the dash and the main box) together, before you try to fasten it all back onto the firewall. It's impossible to do correctly if either box is mounted to the firewall separately.
I've posted a lot of pictures on this thread, to show what I did to modify the box, so the heater and blowing vent still work, with the AC delete panel installed.
I hope this makes it easier for others who want to do this. Other threads I have found are all pretty fuzzy and not very thorough.
I had to do some cutting and then block off a hole that is created when the part that needs to be removed is cut.
First, I had to pull the dash. Then, I had to loosen the nine main screws that hold the HVAC box to the firewall....not an easy task with the engine still in the car. Even with the screws loose, it was a B**** getting the dang box out through the hole in the firewall. I finally took my 4 foot construction bar and smashed it out hitting the bottom of the box, from the outside of the firewall. This part of the box isn't used anyway :)
I will post pics when everything is buttoned up and installed with the AC delete plate. Doing this was a PITA.
Attachment 20465
Once removed, I took the top of the evaporator cover off and then broke/cut the bottom part off. Then I started cutting the rest of the unwanted box off, so that the surface of the remaining box was flat, so it can go against the firewall flush. The part between my fingers is the part that needs to be cut out, so the blower fan can blow air in and through the heater core.
Attachment 20466
Once that part is cut out, there is a wide open space that needs to be sealed off, as shown in the picture below. I actually cut back too far, for some reason, on the rounded part that surrounds the blower fan (I got confused with the shape of the inside of the box and where the air will be blowing, with the AC delete plate on).
Attachment 20476
Nearing completion of cutting the face flat so it sits flush against the firewall, before I cut the "tunnel" into the box. I managed to salvage the old foam gasket. It is actually pretty darn strong and stretchy.
Attachment 20467
I grabbed some empty Pepsi cans and started cutting with tin snips. It was sort of trial and error. The aluminum was pretty easy to work with, but it was harder to shape it than I expected (it wanted to stay in the rolled shape). I used high temp RTV to seal off the corners and holes surrounding the aluminum parts.
Attachment 20468
Since I cut too far back in the curved wall that surrounds the blower fan, I had to run some aluminum pretty far back. I used RTV here to mate the aluminum with the fiberglass. I actually used the curved part of the "blower wall" that I had cut out, along with a clamp, to clamp it against the outer surface of the blower wall, and it sealed very tightly. Notice there is still a triangular shaped hole that needs to be sealed.
Attachment 20469
Here's a better angle to show how far back I cut. What was I thinking?
Attachment 20470
Here it is pretty much completed.
Attachment 20471
Slightly different angle.
Attachment 20472
Looking straight in from the outside.
Attachment 20473
Once the RTV was dry, I painted over my work with some Rustoleum Industrial black paint, even though this part will never be seen, once the box is installed with the block off plate.
Attachment 20474
It isn't pretty, but now there is a "tunnel" for the air to go through, once the AC delete plate is fastened to the box. It should work nicely, once it is all back together and installed onto the firewall. Thankfully, this is not a part I'll ever have to look at.
Attachment 20475
I'll have to figure out some of the little screws that hold the box parts together. Seems some of them poke through toward what used to be the evaporator cover. I'll have to wait for my AC delete plate to arrive, to see if there will be any interference issues.
