I have been told the heater core in my 85 GL is a bear to remove. Is it worth trying to use Bars Leak to fix a pinhole leak that causes the windows to fog up, but doesn't seem to wet the carpet? The radiator is brand new, though.

hi,

  you might get a range of opinions on the replace it idea,  but i'm pretty sure the dash has to be removed to get one out and in,   from a guy that has parted out a bunch of these cars including removal of the heater cores,, i would get another car before i would replace one,, but thats just my opinion.

If it's like my '89 DL wagon, ruparts is right; removing and replacing is not for the faint of heart. Lol I am in the midst of an HVAC rebuild, due to a mouse infestation. I was able to remove the A/C core and heater motor without removing the dash, but I couldn't figure out how to get the heater core free workout removing the whole center stack and the dash. Of course I had a vested interest in removing and cleaning as much of the HVAC system as possible. If it's like mine, you'll find that the foam insulation between the components has deteriorated as well as the foam insulation on the inner baffles. 

 

I know bars leak type products are generally tho be shunned, but in this case it might not hurt to try it, especially if the car is your only transportation...

 

John

I've dont it a couple times and helped One Eye when his heater core needed replacing.

 

Its Easy!

 

Start by unbolting the steering wheel under the dash, its three(I think 12mm) bolts, it will hang down from the firewall. Then unbolt the three bolts at the top of the dash, also 12mm and the 4 under the dash. These are under little cover plates, but they pop of with a screw driver. While you unbolting the steering wheel, disconnect the heater control valve, move the heat selector back and forth to find it, its easy to get to. there's a plastic retainer that holds it on and it pops right off. Once all that is loose, the dash won't fall offf, its held on by a hook in the center of the dash. It helps to move the seat all the way back. lift the dash straight up(once the bolts are out) and it will be free but there is still more to do. Theres three wire harnesses that unplug on each side, they're all color coded so re assembly is easy and you can't physically mismatch them. There's a vacuum line for the hvac system on the pass. side and I can't remember, but I think you can leave the instrument cluster in..I think you can get to the speedo cable after the dash is loose. Thats about it. Slowly pull it off and look for anything I forgot, but I know I'm fairly certain thats about it. You'll need to pull the center console to get the hvac box apart, but that is just and a couple 10mm bolts. The box itself is held together with spring clips and pop off with a screw driver. It may sound like a task, but it really doesn't take long and isn't messy. I can change a heater core in a couple hours and thats not being in a rush, its a good Saturday project.

 

Josh

Also a good time to replace the hoses going into the firewall. Cheap from rock auto. 

 

John