ok i'm having problems gettin to my heater core . i took the bottom panel off under the passenger side. i started to take the bolts out of the part that covers the heater core but i cant get to it unless i take my whole dash off. so i started taking evrything off one buy one ( verry verry painfull) i took my gauges out, my speakers , ecm , etc. this is alot of work to do just to replace a heater core. i still cant get my dash board off . there are bolts that i cant get to behind where my radio would be. so is there anyone that has done this that can tell me how to get to the damn thing

 

I am about to embark on this journey, also.
It is not to difficult to accomplish.
Sounds like you're just not getting those final ones.
In a past thread, it was said that there are four screws covering the outside box.
There was a past thread with a pic that showed where the screws were located. I'll try to pull it up.

 

https://www.thirdgen.org/techbb2/sho...74#post1582674

Enjoy
I will, too!
PS Try doing this heater core swap to a 1974 Corvette. I did, mine!
And I get to do this core swap to my 1985 Blazer, also, Oh joy!

 

Karl, that link you pointed to... I don't know if it was entirely correct for 86-92. I removed/reinstalled the core on my '86 Firebird to allow the body shop to do their welding, and I didn't have to remove the dash at all.

I just used a combination of tools to get to all the 9/32" bolts I could, removed the heater core box's cover, and pulled out the core. There's no need to pull the dash on an 86-92... maybe just take a drive to the local parts store for some universals (socket swivels)!

 

Hey I just did the heater core on my '89 this past weekend. In all honesty, it wasn't THAT bad compared to what I was expecting. Maybe a 3 hour job at most. That top left corner 7mm bolt on the outer box was a bit of a pain. Here's what I did. There was a wiring harness up against the side of the heater box. Move that out of the way, and you can snake your right hand up there and along the top of the box, and feel where the bolt is by hand, while lying on your stomach. To get it out, I used the 7mm socket and an extension (maybe 3", I can't remember), along with an adapter and had just enough room in there to fit it. Not enough room to think about getting a ratchet in there. I grabbed the extension with my right hand, and torqued it. It was a rough go and the shoulder definitely can't take it for long, but with some effort I was able to break the bolt lose and unscrew it. Didn't bother putting it back during reassembly.

By far the hardest part was getting the core + plastic piece that it attaches to back into position in the heater box, and getting the inlet/outlet of the core to line up to poke through the firewall. That took alot of patience and swearing.

Also for some reason that "metal peice" that the install document says to remove was absent from my car?

 

You mean in the link that I was talking about? Yeah, I didn't have a metal strap either, but I do remember the core having a piece of plastic screwed to it, and then that piece of plastic was screwed to the heater box. I'm betting that metal brace was probably for 82-85, and us 86-up guys have the core + plastic piece.

 

Ah ok. Yeah I had that plastic piece the core attaches to with no metal. On the side facing the core, there's a clamp-ish kind of thing on one end, and a strap on the other. First I tried assembleing the new core to that plastic peice with the clamp and strap. But I could not get the core and plastic peice as one unit into the heater box and get the core pipes thru the firewall at the same time and have it all line up correctly. I disconnected the core from the strap side and had the clamp side holding it in place on the plastic peice. This allowed a bit more maneuvering of the core and plastic peice seperately. (BTW I still managed to crack off one of the tabs for the 4 bolts on the plastic peice while reinstalling it, but there was enough plastic around the bolt hole for it to still work correctly) Once I got the core pipes to just poke thru the firewall, I secured it to the plastic peice on the strap side using a small wrench to turn the bolts, and then was able to bolt the assembly to the heater box as it finally lined up correctly.

 

thanx for your help guys ... ok well i got 3 bolts out but the other one is way to hard to get ... i cant get it with a racthet.... i'm gonna try again as soon as it gets warmer out ( wow this is a really good time for the heater core to go ) .

 

Here's a link to an article I wrote up after that aforementioned thread...complete with pictures.
http://www.hioutput.com/tech/heatercore.html

Pete