Heater/AC Ducts Repairs/Mods Talk

[89Suburban]

I am going to be tearing my dash apart in the next few weeks. My heater ducts leak horribly into the dash boar instead of directing that air where it is supposed to go. I will also probably remove anything to do with the A/C. What I want is to ge the heater and defrost blowing like new and have fresh sealed duct work for those 2 positions.

I never had this stuff apart before, and never saw pics or a write up on it, so I will start one, but I am looking for yous guyz experiences stripping and rebuilding the dashboard duct work or modding it.

Plese post whatever you think needs to be shared to make this project move along smoothly.

Last winter I had a thermometer laying in the ash tray. It would get very hot, like up to 90 degrees, and the metal part of the dash would almost burn your hand if you touched it, but the air coming out of the floor duct was very poor CFM wise, like you could barely feel it blowing out, and the fan works fine. It's just leaking away under the dash somewhere.

I am also thinking about the possibility of running modified duct or ducts up the center hump of the floor, under the front bench seat and venting out to the second bench seat floor area to help distrubute more heat to the kids in the center seat.

 

[bucket]

The heat and AC use the very same duct work. You won't be able to ditch anything unless you only want to use the floor and defog positions.

 

[89Suburban]

The heat and AC use the very same duct work. You won't be able to ditch anything unless you only want to use the floor and defog positions.

Ok.

I also want to get rid of the ac housing on the firewall too.

 

[bucket]

That should work out ok I think. You would need to leave a portion of it there though, the part with the blower motor. Then form a small duct to direct the air into the firewall. Probably have to cover up a large hole in the firewall also.

...That's just speculation though, never done it myself.

 

[Irishman999]

You might get some vacuum line ready. I had mine apart last winter to do the heater core and all the factory hard lines snapped off. Its a cluster **** under the dash.

 

[bucket]

You might get some vacuum line ready. I had mine apart last winter to do the heater core and all the factory hard lines snapped off. Its a cluster **** under the dash.

Yeah, but your stuff gets baked doesn't it? Things don't seem to get nearly as brittle over here.

 

[Irishman999]

Good point, it might just be a western us thing but I snapped damn near every vacuum line under the dash EASILY.

 

[89Suburban]

Thanks for the tip Imann.

 

[f1shman]

My advice would be to buy a blend door clip (LMC, GM) ahead of time so that you have it on hand. Yours might not be broken yet, but it's always better to replace it if you are going to have the dash apart anyway. Think of it as preventative maintenance. While you are working on the duct work I think you'll find that most of the hoses are cut too darn short from the factory. As such, they don't like to stay in place and you have to stretch and manipulate them to get them to contort back into position. A big help to get them to stay together after you make all your changes is to buy some of the silver tape that HVAC techs use on sheet metal ducting. Don't get me wrong, I don't mean the silver duct tape that people use to hold together their bench seats. It's "foil backed tape" that you want, like an aluminum foil with adhesive on it. ( Home Depot Product Link ) Just wear gloves when you put the stuff on because it will cut you if it folds into any kind of point. If you are removing your heater core you might want to get some 1" wide adhesive weatherstripping foam as well. That way if the foam inside the box that the core sits up against is worse for wear you can replace it and keep the air moving through the core instead of around it.

Other than that I just want to second the previously mentioned fact that you want to watch out for your vacuum lines while you are in there. Getting a crack or break in one of those where you don't notice it will ruin your day.

 

[89Suburban]

My advice would be to buy a blend door clip (LMC, GM) ahead of time so that you have it on hand. Yours might not be broken yet, but it's always better to replace it if you are going to have the dash apart anyway. Think of it as preventative maintenance. While you are working on the duct work I think you'll find that most of the hoses are cut too darn short from the factory. As such, they don't like to stay in place and you have to stretch and manipulate them to get them to contort back into position. A big help to get them to stay together after you make all your changes is to buy some of the silver tape that HVAC techs use on sheet metal ducting. Don't get me wrong, I don't mean the silver duct tape that people use to hold together their bench seats. It's "foil backed tape" that you want, like an aluminum foil with adhesive on it. ( Home Depot Product Link ) Just wear gloves when you put the stuff on because it will cut you if it folds into any kind of point. If you are removing your heater core you might want to get some 1" wide adhesive weatherstripping foam as well. That way if the foam inside the box that the core sits up against is worse for wear you can replace it and keep the air moving through the core instead of around it.

Other than that I just want to second the previously mentioned fact that you want to watch out for your vacuum lines while you are in there. Getting a crack or break in one of those where you don't notice it will ruin your day.

And the vacuum lines look as they are arranged in a harness form, so if anything does break, or I just would like to replace them all anyway, then that is a night mare in itself because of the junction blocks, right?

I have a roll of camper foam tape laying around, can I use that for the heater core if I open it up that far? I guess it wouldn;t hurt to look into a price on a new HC and replace it while it is apart too then...

Thanks for the tape link.

 

[89Suburban]

Maybe I can look around for a replacement vacuum harness? Anybody look for that before?

 

[dhamp]

Do we have any auto A/C techs on here? We may need to go recruitin!

 

[89Suburban]

Here is a page from LMC. Looking at this, I can remove the vent ducts and block off the holes. Leave the vent's in hte dash for cosmetic look. and re-seal some of the connections on thouse housing pieces.

Heater core looks fairly affordable, I will shop around for a new one to install.

However no vacuum hose assembly or harness seems avail here. Might have to check the dealers?

 

[89Suburban]

****, heater core mouints on the outside under the hood, right? Maybe I will shelve that idea until the inside is done.

 

[89Suburban]

Red is what I will remove and blue is what I will block off. I don;t see anything here for the defrost and floor heat ducts.