I have to install a new heater core in my 79. I have been looking at the install and I think it is going to be terrible. Does anyone have any tips/hints on how to make this go easier, or am I making it harder than it looks.

 

It is NOT EASY.............Especially if it is an A/C car........there are several papers including one by Juliet that is an excellenbt reference....Remember the heater core is installed in the car and then they build the car around it :lol:

 

I'm about to jump into it myself. Last year Juliet Page posted some pictures of the change out on her 70 convertible with air. It requires going through the dash to get to the core. If you have A/C that is the only way to get to the core.
If your car doesn't have air then it is a piece of cake. Paul79 posted some pictures a couple of years back of his replacement of the heater core on his 79, and it was easy to get at from the engine compartment. All he had to do was pull the cover off the outside and the core was right there.
But if your car has air conditioning it is a different story.
I know that it requires removal of the left side of the dash, the center gauge cluster and some bracing rods that run across the firewall. On a pre-77 'vette you can get the left side of the dash and the center cluster out without too much trouble. I think on your car it will require the entire dash be pulled.
If you replace the core, PLEASE have the new core tested before you install it. There have been a number of cores that leaked right out of the box, and I'd hate to see you have to do the job twice. Also buy the correct core for your car, if you go to a parts store and get one there is a chance that you'll end up with a generic core that sort of fits your car. Buying directly from GM or an A/C Delco distributor is probably your best bet.
Also order a heater/AC box reseal kit, plan on replacing all the foam seal, it will improve your air flow 200%.
Also get a set of the correct style heater hoses, the molded curves sure make it easier to hook up. Zip has them in the restoration store available here on the forum. They have the NCRS correct hoses and correct style molded hoses (without the correct markings) for about half the price.

 

Who needs a functioning heater ??????? :lol:

 

That's what I thought too. I didn't have a heater on a 69 Camaro I used to own. Worst thing I ever did was hack up that A/C box so those headers would fit. Then no heat or A/C. What a stupid-azz I was!!

Think about it like this. If ya replace a few more things on your way out, then it makes a lil mo betta. My heater core has no hoses hooked to it. I don't know if it's bad or what. Actually, it don't matter cause I'm gonna replace it anyway. Gonna firm up the ductwork and replace my dash guages with some Autometer units on the way out. So, whilt you have the dash apart, do some other stuff while you're in there. Then you wont hafta have your dash off again for a decade or two.

 

Listen to Smokehouse69! Very good / sound advice! In addition, suggest you pull the heater blower motor and replace motor or at least clean cage, and then clean the bottom of the box through the motor hole as best you can with vacuum cleaner and air hose, as tipically you'll find lot's of leaves / crud in this area from all the years of exposure to the elements/sitting outside.

Don't know that I'd say replacement of heater core is difficult, but I will say it is "involved" and very time consuming..........a great winter project. Remove your seats, pull the front carpet, and be prepared to do a lot of cleaning and you'll probably run into many "while I'm at it, and this far" projects.

 

I just replaced a core in an 82. I can give you some tips.
first of all there is only one nut on the top of the heater box under the hood that has to be removed. after the removal, jack up the car and remove the clamps from the heater hoses and use a utility knife to cut the hoses for easier removal. If you look up into the evaprator box where the heater core tubes come through, you will see a rubber gromet with two holes that the tubes come through. remove this grommet. On the inside of the car remove the center gauge cluster which consists of radio and four screws plus two 1\4 or 5\16 bolts that bolt the gauge bezel to the shift console (these screws are mounted up from the bottom of the shift console and screwed into the gauge bezel. by the way before you can gain access to the heater control unit or the screws that mount the gauge bezel you have to pull the two carpet insert pieces that cover the shift console. these are mounted with 3 screws per side located approx: one in the foward half under the dash, one in the center just before the back of the shift console and one in the rear half just before the rear bulkhead under the parking brake console. be careful when pulling the plug from the printed circuit board and at this point I would probably pick up a new printed circuit board since the contacts will probably pull loose anyway. there is also another lead that plugs into the top gauge light which is easy to remove and one more three wire plug that mounts to the oil temp gauge, after you pull the glove box insert out. in fact pull the glove box insert first. remove the 2 screws on the door body post that holds the r\s of the dash tight and this will allow you to pull the right side of the dash loose enough to remove the rest of the parts ( the top of the dash just lides out of a mounting clip). pull the center duct out which is only held in with one screw. unbolt the heater door cable (mixing door) from the housing, pop off the retainer and take the cable off. disconnect the vaccum plug off of the heater control unit to free up the vacuum lines and remove the vacuum line from the right side diaphram that is right above the kick panel. remove the remaining bolts from the inside of the heater box (3) wiggle the box loose and as you twist the box down remove the one vacum line from the diaphram that is located on the other side of the heater box (firewall side in the inside of the car). you will probably have to play with twisting the box around since the core tubes take a 90deg. bend outside the firewall and sometimes the tube are so tight to the firewall it feels as though there is still one part bolted together. once the box is out you have to seperate the face by removing the old seals to access the screws to get at the core. I used self sticking foam insulating strips to reseal everything and you just have to buy 90deg. molded heater hoses for the new install from any auto parts store, one hose is 5\8 and the other is 3\4. one note on the install: when you go to reinstall the box and new core have someone under the car with a long screwdriver or extension to help "move" the tubes alittle since they were meant to be installed without an evaproator box. Be careful with these tubes but they can and probably will have to be bent slightly in order to accomplish the installation the only plus is that you can't puncture the core because of the 90deg angle but you probably can brake the solder joint loose if you aren't careful although again because of the 90 angle it would take some doing. you just don't want to ruin the hose falres at the end of the tubes. do yourself a favor and pull it out one night and install the next morming with a clear head to prevent frustration. It's not impossible to do but it does take patience. also make sure you cover the carpeting to prevent antifreeze or water from staining it. also as an after thought don't have your old core repaired since a brand new core only runs about $50. GOOD LUCK Jeff. by the way, the blower motor comes out from the outside of the car and isn't involved with this job at all. if you need further advise you can email me at : WCJ0937@optonline.net


[Modified by wcj, 10:27 PM 11/27/2002]


[Modified by wcj, 10:29 PM 11/27/2002]

 

Well I joined the ranks of the heater core squadron. Juliets info was a big help, as was some other threads.
UNFORTUNATELY MY NEW CORE LEAKED. I have read on here that its happened to some other forum members, but NEVER thought it would happen to me. Oh Well!!!!
Time to start over. :cry :cry :cry

 

I replaced my heater core last year. I have a non air car. The whole job took me about 8 hours. My core had to be removed from the interior side.

 

The job on my 1979 (non-A/C) took less than one hour.





Finished.



[Modified by paul79, 8:05 PM 11/27/2002]


[Modified by paul79, 8:16 PM 11/27/2002]

 

RLaFarge:

I recently completed a heater core replacement on my 78 A/C car and indeed it was a project. Patience, a six pack and time and it's quite doable. Here are the facts:

Your 79 is a one piece dash that does not have to be removed.
Definitely pre-test the heater core before installing...saves a bunch of work. The failure rate on replacment units are poor.
Invest in a quality unit otherwise you'll have "fit" problems once its in place.
The 78 and 79 shop manuals are not correct but reflect removal for two piece dashes (68-77).
It's a good time to check the entire functionality of your heat A/C components like actuators, doors, etc.

I found the 78 and 79 shop manuals incorrect and as a result I documented the entire project. In fact, I'm looking for some feedback and willing to share, providing you can let me know how well the steps guide you through the project.

email me if interested.