You guys have confirmed that the heater core is shot. Any words of wisdom on changing one of these. Sad thing is, last weekend I had the interior stripped and put in heat barrier and new carpet, sure would have been a good time to do this then. 71 with A/C

 

From what I understand reading this forum is that a car with AC you have to pull it from the engine side.Without AC you can go in under the dash.Pull out the pass. seat and what looks like half the dash.Either way it's no picnic.I know this isn't much help,just trying to point you in the right direction

 

I replaced my heater core this fall. I have an A/C car. you can only change it from the inside. Its a PIA but you can do it. Do yourself a favor and while your at it change the lamps in the dash too.

I tried to capture the pictures from this post but maybe the write up will help some.


Heater Core Replacement on a 1970 Corvette Convertible with Air-Conditioning
After a lot of deliberation, and about a month straight of bronchitis, and the realization that I just didn't have enough hours in the day to undertake a heater core replacement myself, I decided to take my beloved grunge monster, Sophia, '70 Corvette Convertible with AC, to the ONLY place I trust: Tony's Corvette Shop in Gaithersburg, Maryland. It was by far the best money I have spent thus far avoiding what has to be one of the most involved restoration tasks! The approximate 8 hours of professional perfectionist labor for this core replacement has freed me to focus on the other far more appealing aspects of vette restoration (like scraping 30 years of accumulated goo and ooze off the undercarriage). <grin> I figure 8 hours of a pro, who has done this zillions of times, would equate to at least 40 hours of myself. This puts the task well outside my short term disassembly and reassembly memory window... Heck, I'd still be fumbling through the AIM pages at this point, trying to figure out how to get it all apart instead of driving my corvette a few short days later. :-) So, with special thanks to Tony's Corvette for documenting the process with digital pictures, and to Eddie, the other C3 whiz at Tony's, for performing the labor, I'll present Sophia's heater core replacement project....
(I hope I didn't butcher the descriptions too badly. <grin>) ~Juliet

And this is why, with an Air-conditioned car, you can't get to the heater core from the engine bay.

This is a view from the underside of the car. You can see where the heater hoses go into the heater core box.

Here is the dash area with the front pad removed. The two components with the 'heat fins' are convectors from the AM/FM Stereo Radio unit (RPO U79).

Here is a close-up of the instrument cluster and AC vent. Note the cracked gauge bezel. (It was like that when I purchased the car unfortunately).

After the cross brace and the Radio Convector has been removed, this is what you see:

A little further to the left, behind the instrument cluster one will find this:

Once the ducting and core box have been removed, there's plenty of room behind the dash!

Here is the core box with core removed on the bench.

BTW, the core removed was the original Harrison Core dated K-69 (My car's build date is B-18-70) Here's a closeup of the factory core.


Good Luck,

John

 

Actually it is the other way around. The heater core in a car with air is taken out from the passenger compartment and taken out from the engine side in cars without air.

There is nothing too difficult in replacing the heater core in a car with air but there is a lot of stuff that needs to be taken out to get to it. R/H lower dash pad, center gauge bezel, various vacuum hoses and bracing and the heater hoses. There are three screws in the heater box that are taken out from the inside of the car and one nut that needs to be taken off from the engine side.

Jay

 

Here is a good web site to visit: heater core replacement

 

Thanks everyone for the advice