Heater core Help .
Racer
Joined: Dec 2001
Posts: 328
Likes: 0
From: Dallas County Texas
It wasn't a lot of fun on the '75...
I assume they are similar.
I did all of mine as all one part of an entire dash, HVAC, etc. rebuild and....wow....what a long nightmare, although I loved the results. (The HVAC part wasn't all that successful, to be honest!
)
The heater is kinda at the bottom of the pile of all the ducting and dash guts. Once down there, it's not all that hard. I found every duct was gapped apart. Every controlling vacuum line was off or decayed. The little control doors and pods and such - didn't.
While I was concentrating most of my time on the digital dash conversion and modern radio conversion and wiring and such, I know a number of the 20-odd tubes of epoxy and couple of rolls of black duct tape went in the heater area too.
The little control cables also seemed to be a nuisance routing, IIRC. I think the main one that goes to the control panel behind the big array of vac hoses kept falling off until I modified it somehow.
I did all of mine as all one part of an entire dash, HVAC, etc. rebuild and....wow....what a long nightmare, although I loved the results. (The HVAC part wasn't all that successful, to be honest!
)The heater is kinda at the bottom of the pile of all the ducting and dash guts. Once down there, it's not all that hard. I found every duct was gapped apart. Every controlling vacuum line was off or decayed. The little control doors and pods and such - didn't.
While I was concentrating most of my time on the digital dash conversion and modern radio conversion and wiring and such, I know a number of the 20-odd tubes of epoxy and couple of rolls of black duct tape went in the heater area too.
The little control cables also seemed to be a nuisance routing, IIRC. I think the main one that goes to the control panel behind the big array of vac hoses kept falling off until I modified it somehow.
Pro
Joined: Sep 2004
Posts: 517
Likes: 0
The heater core looks to be a huge pain. Unless you really need a heater, I'd just block the lines and call it a day. The compressor is easy to change, just don't let the weight catch you off guard. That **** is HEAVY!!!
Thread Starter
Racer
Joined: Aug 2001
Posts: 431
Likes: 0
From: ny
Originally Posted by WhichVette?
The heater core looks to be a huge pain. Unless you really need a heater, I'd just block the lines and call it a day. The compressor is easy to change, just don't let the weight catch you off guard. That **** is HEAVY!!!
Race Director
Joined: Sep 2002
Posts: 10,362
Likes: 5
From: San Diego - Deep Within The State of CONFUSION!
I had my whole dash apart last summer and put new foam seals around all the duct work. Now my system blows LOTS of air. But even though I pulled the heater core box off the dash, and yea it's a lot of work to get down to it, I never could OPEN the damn box to replace the core.
By that time, my engine had been in for over a year. And when I put the engine in, I had plugged the water holes in the pump and the manifold, so the heater core was already bypassed.
I armwresled the box for an hour, had another beer, and just put it back in
with the old heater core inside it. 
I was getting really frustrated and was bound and determined to start the reassembly.
Next day I returnd the new heater core I'd bought and I still have the old one in place. Lucky me I don't need it.
By that time, my engine had been in for over a year. And when I put the engine in, I had plugged the water holes in the pump and the manifold, so the heater core was already bypassed.
I armwresled the box for an hour, had another beer, and just put it back in
with the old heater core inside it. I was getting really frustrated and was bound and determined to start the reassembly.Next day I returnd the new heater core I'd bought and I still have the old one in place. Lucky me I don't need it.
Racer
Joined: Apr 2005
Posts: 339
Likes: 1
From: San Diego CA
I pulled the heater core on my '71 a few months ago. It does take a little time.
The right-side dash has to come off which means the top dash pad should come off. The center console needs to come out since the a/c ducting needs to be removed. Behind the ducting, and to the right of it are the three screws from the inside, and one nut on the outside firewall that hold the plenum in place.
The two hoses obviously need to be removed from the bottom of the car at the heater core. On the inside, various cables and wires need to be moved aside, then the plenum will pull toward you (assuming you are sitting in the passenger seat). The disconnected heater core will come out with the plenum. Assembly is reverse...
The right-side dash has to come off which means the top dash pad should come off. The center console needs to come out since the a/c ducting needs to be removed. Behind the ducting, and to the right of it are the three screws from the inside, and one nut on the outside firewall that hold the plenum in place.
The two hoses obviously need to be removed from the bottom of the car at the heater core. On the inside, various cables and wires need to be moved aside, then the plenum will pull toward you (assuming you are sitting in the passenger seat). The disconnected heater core will come out with the plenum. Assembly is reverse...
Racer
Joined: Dec 2003
Posts: 263
Likes: 0
From: Kernersville Nc
I replaced the heater core in my 72. It took 4 hours. I did most all the work taking the passenger side dash apart. The only thing i had to do under the car was connecting the heater hoses. There was a big rivet holding the heater core box on that i had to drill off with a 12" bit. Other than that is wasn't bad.
Eric
Eric
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Drifting
Joined: May 2005
Posts: 1,909
Likes: 6
From: Lake Arrowhead - Georgia > 72 Base Coupe & 74 BB Roadster
Did the core on my 72 a month ago. Don't get in a hurry. Remove the following....after you drain the cooling system and disconnect the hoses from the core.
Center instruments...mark the wires for the back of gauges.
Radio....
right side plastic kick panel
front of passenger side dash (map pockets)
Then start taking the duct work out...eventually you will get to the actual heater box. There are 3 nuts inside - and ONE nut outside under the hood that hold the box in. Remove the box and break it open on a bench. Mount the new core and slip back through the firewall from inside. Clean all your parts up and put it back together.
As you go ... take some pics with your digital ... you might need them as you re-assemble. Good Luck .
Center instruments...mark the wires for the back of gauges.
Radio....
right side plastic kick panel
front of passenger side dash (map pockets)
Then start taking the duct work out...eventually you will get to the actual heater box. There are 3 nuts inside - and ONE nut outside under the hood that hold the box in. Remove the box and break it open on a bench. Mount the new core and slip back through the firewall from inside. Clean all your parts up and put it back together.
As you go ... take some pics with your digital ... you might need them as you re-assemble. Good Luck .
Team Owner
Joined: Aug 1999
Posts: 30,995
Likes: 98
From: Ontario
Safety Car
Joined: Jun 2004
Posts: 4,652
Likes: 80
From: Lakeland Florida
Hello,
Here is another guide that was posted on the Forum.
http://www.corvettefaq.com/c3/C3CoreReplacement.pdf
kdf
Here is another guide that was posted on the Forum.
http://www.corvettefaq.com/c3/C3CoreReplacement.pdf
kdf