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Heater Core Removal / Installation

7

78SilvAnniv

Guest
This past spring my heater core sprung a NASTY leak! I limped on home and we tied everything leading to and from the heater core off, and Kenny began removing the ducting and glove box...

...now with Fall on the way, I want this completed BEFORE I need my heater!

What are we in for?
I'm pretty sure it will be a frustrating job, and I'm sure the h-core won't come out through the firewall, engine side.
Will this be a 1-day job?..a 1-weekend job?..or should I hire it out to a garage after I get the parts?
What are the risks the dash will suffer upon its' removal?
Heidi
 
7

78SilvAnniv

Guest
A topic search

Revealed no instructions or tips for removal / installation of heater core.

Most comments were:
It's a PITA
Takes over 15 hours *one person w/ C4 completed the job in 5 hours.

Best bet seems to be a Vette Fever article several years old with detailed instructions and photos. I don't have Vette Fever magazine. Will they have this article available in on-line archives?
Heidi
 
Joined
Aug 29, 2001
Messages
3,236
Location
Norcross, Georgia, United Stat
Corvette
2017 Arctic White Grand Sport
Heidi,

Removing the dash can be a difficult project. I had my dash completely out last year and exactly how difficult it is depends on whether or not you will need to remove the driver's side dash pad to get the ductwork out to access the heater core. If you only have to remove the passenger side, center instrument cluster and dash pad it isn't too bad.

The driver's side was much more difficult for me. I had a difficult time getting the pad over the steering wheel collar, even after I lowered the steering wheel, and back under it when reinstalling. I kept pinching the vacuum hoses to the lights and having to remove it again. Putting the lights and other wires back in the back of the dash was not too difficult with a mirror on a stick. My problem here is that it is a tight space and I am a pretty big guy.

I can't speak to removing the ductwork as I didn't do this.

Whatever you do, make sure you put screws in baggies, take pictures and/or diagrams, etc., as there were a lot of pieces with different size screws that need to go back in the right places.

Having spouted all this bad karma, be aware that I did it and I am not very mechanical. If you are carefull the dash should go back in good as new. While I had mine out I dyed it back to the original color with good result.

If you kept at it and had no problems you could definitely have it done in a weekend.

Do yourself a favor and have the core pressure checked before you put it in. On occasion new ones are found to be leaking but only after the dash is all put back together.

Good luck.

Bob
 
7

78SilvAnniv

Guest
Thanks

"new ones are found to be leaking but only after the dash is all put back together"

:duh

I hope we haven't bitten off more than we can chew!

The ducting he removed was from under the glove box. I didn't realize the entire dash did not need to come out!? I think we can handle the instrument area better (UH-OH...I just thought of the stereo...what a freakin' nightmare!) than the entire dash.
78's dash has two small cracks. Not very noticeable unless you know where they are. Like I do. I just don't want them getting noticeable to everyone!
Heidi
 
Joined
Aug 29, 2001
Messages
3,236
Location
Norcross, Georgia, United Stat
Corvette
2017 Arctic White Grand Sport
The ducting he took out is likely just for the a/c to travel from the center of the car to the vent ball in the panel. The heater is behind that much more substantial black box bolted to the firewall where the air comes into the car.

Take your time. You can do it. I also had two cracks in mine and bit the bullet and replaced that very expensive ($300+) piece.

The more I think about it the more I think you won't have to take out the driver's side pad. If that is the case, I would definitely do it myself. If not, I would consider taking it in.

Here is a quote I plagarized from a site that will go unmnetioned.
----------
I just finished doing my heater core on a 77 C3 for the third time, so I think I know what I am talking about. The last time took me all weekend but I work very slow and changed out my console as well. Here is what I have learned (at least on a 77). One: You do not have to mess with the driver side of the dash -- you can do the job by only removing the gauge cluster and passenger side of the dash; however, there is a trick to not having to mess with the driver's side. The trick is that once you disconnect the hoses, loosened the plenum from the firewall and removed the shutoff valve and cable on top of the plenum, you must slowly TURN the plenum so that the side facing the firewall is on top. This turning action will put some stress on the remaining duct work that you left installed behind the instrument cluster but it can be removed and installed this way. If when you try this, you simply do not feel comfortable with the stresses you are putting on the remaining duct work, then you may decide to remove the duct work behind the gauge cluster but that may involve messing with the driver side of the dash. Once you remove the heater core, you can figure the rest out for yourself, BUT here is the MOST IMPORTANT TIP: connect the heater core hoses to the new core after you have installed it in the cradle and test it while it is sitting on your garage floor (engine running) to make sure it is not leaking before reinstalling the heater core into the dash. The reason is because the tubes on the heater core do not fit very nicely in the cradle and if you force them, the tubes will leak where they are joined at the top of the core. To ease the tubes in the cradle, only loosely attach the cradle bands at the top and bottom of the core. Do not tighten the bands down until you have slowly screwed the clamp between the tubes down. If you tighten the bands first, you risk putting too much stress on the tubes where they enter the core. Once you have tested the core outside the car, you can install it, but I recommend that you buy the heater core gasket kit. Its about $40, but the kit has all the gaskets needed for the duct work joints. Good luck and please let us know what you learn as you boldly go forth.
_______

I was looking for another post that I had seen recently about checking the air intake area for the HVAC system. It is in that area and as I recall, they recommended taking a look at this as well while you had the heater core out to make sure that it works, basically closing the flap on max air and opening it on regular air and that the flap, which is plastic, is solid and does not deflect excessively. Evidently if this does not funtion properly it will introduce hot air into the HVAC system and is one of the problems with hot air in the cockpity. I'll take another look and see if I can find it for you these evening.

Bob
 
Joined
Aug 29, 2001
Messages
3,236
Location
Norcross, Georgia, United Stat
Corvette
2017 Arctic White Grand Sport
Heidi,

The other thread.
----------------
Like most of you I've battled the problem of cockpit heat. I think I've finally found a problem in my 74 that may be common to a lot of C3s and which may cause heat to come in to the cockpit no matter how much insulation or sealing is done to the heat/AC system. Over time I've noticed that I always got an "engine" smell in the cockpit. I figured it was air coming out of the hood and being drawn into the heating system through the air intake in the wiper trough or air leaking into the system through the heater box. I put a wiper cover on earlier this year and I could see that the hood sealed really well in this area so this shouldn't cause a problem with air leakage past the gasket. Since I pulled my heat/AC system out last winter and resealed everything I discounted this as a cause for heat leakage also. When doing the heating system I also installed a shutoff valve for the coolant. I also insulated my entire cabin so I'm not getting heat through the floorboards or the body. This left the air intake on the system as a possible source. I removed the right hand dash pad and kickpanel which exposed the flapper mechanism for the inside outside air control. I removed the vacuum motor and flapper mechanism by unbolting the two bolts that hold the motor, moving it out of the way, and unhinging the flapper. This is done by pulling down the top spring loaded pin, pushing the door into the fenderwell and twisting it so that it can be removed from the inside of the car. I then started the engine with the hood closed and the heat/AC off. I felt hot air coming into the plenum from the engine compartment. This plenum is secured with the same adhesive that holds the rest of our body panels in place and like those the adhesive will dry and crack over time. Anyone who has dealt with stress cracks on the fenders can attest to this. Remember also that air leaking into this plenum will be coming directly off the exhaust system and with headers the problem is exaggerated. To seal this plenum I used windshield sealing caulk. You can get this at your local parts store for around $5 a roll. I used the cault to seal around the entire perimeter of the plenum, or as much as my arm would reach since you're working through the flapper hole. The most important areas to seal are the forward and lower area since that's where the majority of the heat will come from. The rear area is sealed against the forward door jam and really shouldn't leak hot air. After doing this I repeated the test with the engine running and felt no heat entering the cockpit. I reinstalled everything to complete the job. I've only driven the car twice since then but I can tell you that there was a vast improvement. I took the car to work on a day when the temperature hit about 85 degrees. Before the fix I would have had to have the AC running or the heat would have been unbearable in the footwells and even worse with the t-tops off. I ran the car home that day with the t-tops off and the footwells were no hotter than the rest of the car. I've also noticed that the AC tends to run a little cooler by not having to fight the heat coming into the system. So far I also haven't had that "engine" smell anymore. I'm hoping that as I use the car more, in different situations, I'll be able to report more benefits from this fix but until then I thought I'd give a heads up to everyone. For details on the cockpit insulation go to my website. You'll see the article on insulation and also what you have to remove to reseal the heater box.

Bob
 

69MyWay

Well-known member
Joined
Jul 3, 2001
Messages
4,364
Location
Auburndale, Florida
Corvette
1969 Killer Shark
This is not your exact year model parts, but it gives you a really good idea of how that heater core sits in the box. Especially the last picture. As you can see, the way the in/out hose manifold turns from the core, you want to be very careful not to bend or apply too much pressure on them trying to slip them back throught the firewall.

Should you get a professional to do it? Well, that is up to you. I honestly think you can handle this job on your own, and save some major bucks!

Keep us posted.

How about taking some "step by step" photos?
 

Guy

Proud to Support the Corvette Action Center!
Joined
Apr 12, 2001
Messages
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Location
New England
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2010 CRMT Grand Sport Coupe
Joined
Aug 29, 2001
Messages
3,236
Location
Norcross, Georgia, United Stat
Corvette
2017 Arctic White Grand Sport
Scan #1 of manual on the introduction of outside air into the cowl intake.

Right click on the image and save it to your hard drive. Then you can open it with any image editor and increase the size to make it more readable.

If you can't read it, email me and I'll be more than happy to email you larger scans.
 
Joined
Aug 29, 2001
Messages
3,236
Location
Norcross, Georgia, United Stat
Corvette
2017 Arctic White Grand Sport
Scan #2 of manual on the introduction of outside air into the cowl intake.

Right click on the image and save it to your hard drive. Then you can open it with any image editor and increase the size to make it more readable.

If you can't read it, email me and I'll be more than happy to email you larger scans.
 
7

78SilvAnniv

Guest
Thank you guys!

I will show Kenny this thread tonight when he gets home from work...and find out if this is something he thinks he'll have the time and energy for.

If not...I'll bundle all of the information up and go see how the new Corvette shop in town treats me!

And Chris...what is with SCARING me with those pics! Yikes! :eek
I didn't realize there'd be so many parts, or are those pics heater core and AC stuff, not just heater core? Does all of that have to come out just for the heater core?

I just might wind up calling this project the Hater Core Project! ;)
Heidi
 

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