Heater Core Replace on a 75
Thread Starter
Safety Car
Joined: Oct 2004
Posts: 3,725
Likes: 5
From: Minnesota
Heater Core Replace on a 75
My other problem with my new engine installation is a bad coolant leak from the area of the heater core. This was the one item that I haven't replaced or gone through. I'm guessing I damaged it when taking off one of the old hoses 
. How do you replace it (it looks like a mess) and are the $50 ones from Corvette Central as good as a Delco from Bairs for $85 and do I need a new gasket kit? It's a 75 with AC. For myself I would just plug the hoses but the wife doesn't want to ride around wearing mittens and snow pants 
. Thanks. John
. How do you replace it (it looks like a mess) and are the $50 ones from Corvette Central as good as a Delco from Bairs for $85 and do I need a new gasket kit? It's a 75 with AC. For myself I would just plug the hoses but the wife doesn't want to ride around wearing mittens and snow pants . Thanks. John
Instructor
Joined: Jan 2002
Posts: 185
Likes: 0
From: Surrey BC
I hate it when new problems show up after putting it all together! I did mine ('75 with air) about 1 1/2 years ago.... no fun at all. Basically, you need to take everything from center of dash over to the right out, just keep pulling stuff out till you see heater core. I believe some recommend connecting the hoses to new one then feeding them through. Can't remember if I did that or not, too many 
Pro
Joined: Nov 2004
Posts: 659
Likes: 0
From: Flower Mound Texas
I just replace the heater core in my 75 with air a few months back. The first core I bought off ebay did not fit properly, so I returned it. I bought a new core from Ecklers and it fit fine - no complaints.
Lyndave75 is right. Start at the passenger side dash and you'll end up working your way left and up. I already had my entire dash out to fix other problems, but I don't think you need to pull the driver side dash out. There is either one or two bolts in the engine compartment up against the firewall that need to be removed. Give yourself a weekend to do it. The old adage about GM building the car around the heater core has some merit. It's not a hard job...just takes some time.
Lyndave75 is right. Start at the passenger side dash and you'll end up working your way left and up. I already had my entire dash out to fix other problems, but I don't think you need to pull the driver side dash out. There is either one or two bolts in the engine compartment up against the firewall that need to be removed. Give yourself a weekend to do it. The old adage about GM building the car around the heater core has some merit. It's not a hard job...just takes some time.
Burning Brakes
Joined: Apr 2003
Posts: 844
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From: Central KY
I plan to replace both the heater core and the evaporator - and rebuild the air box with Dr Rebuild's seal kit - when I pull my engine this summer. Eliminate all the problem areas there at once!
Team Owner
Joined: Aug 1999
Posts: 30,995
Likes: 99
From: Ontario
Advanced
Joined: Jan 2005
Posts: 99
Likes: 0
I replaced the core in my '72 a couple of years ago...did the same thing you did, broke the braze where one of the hose tubes went into the core while trying to remove a hose. Fortunately, that particular car was not an A/C car! And believe me, that WAS fortunate. I began to attack the job from the interior, ripping out virtually the entire center gauge section, rightside underdash, heater box, etc, etc. I then, by some devine intervention, became wiser, and moved to the engine compartment firewall. Did the job in half the time! You, my friend, having an A/C car, will not be so fortunate.
I purchased my core from Corvette Central. It fit and worked fine. I would recommend purchasing a new gasket kit. I tore the heck out of my old one, when the core came out. The old gasket had almost disintegrated in some areas, there were leaves and all kinds of debris down in there. The kit comes with a gasket for the flap as well. Good luck.
Kevin
I purchased my core from Corvette Central. It fit and worked fine. I would recommend purchasing a new gasket kit. I tore the heck out of my old one, when the core came out. The old gasket had almost disintegrated in some areas, there were leaves and all kinds of debris down in there. The kit comes with a gasket for the flap as well. Good luck.
Kevin
Last edited by kcmk; Feb 3, 2005 at 05:24 PM.
Thread Starter
Safety Car
Joined: Oct 2004
Posts: 3,725
Likes: 5
From: Minnesota
Thanks for the replies. They built the car around the heater core? 
Great. I thought they built it around the trailing arm bolts. I know the fan didn't seem to push real well so I guess I may have had to go in there at some point anyway. Thanks again. John.
Great. I thought they built it around the trailing arm bolts. I know the fan didn't seem to push real well so I guess I may have had to go in there at some point anyway. Thanks again. John.
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