I'm hoping to start this project tomorrow. I found a good thread with lots of pics on this topic. I see mention of a video on this but I didn't find a link. If anyone has one, pls reply.
This all started after it started overheating due to a clogged radiator and I had it 'thoroughly' flushed. I'm wondering if the extra flushing caused this leak. Not that I had a choice.

I can't spend all day on this and only have the weekends anyways, so this might drag out for weeks but I do need to use the car a bit. Is there a problem starting the car if I remove the airbag - ie. some safety issue that the computer detects on start?
Seems like I should be able to drive it normally even with the dash all apart once I get the heater core bypass in.

I noticed this was a problem when I put some bags on the passenger side floor and it was wet with coolant.
I assume I have to pull the carpet to get all clean. Any thoughts anyone can add on that?

TIA

 

Moved to C4 Tech for assistance.

 

I posted this URL in past (95 coolant leak thread)

https://www.vettetube.com/1984-1996-...c4-corvette-2/

 

Thx. I saw that video but I followed this 95/96 step by step cause of the airbag.
https://www.corvetteforum.com/forums...placement.html
Mostly great instructions, a few more pics wouldn't hurt especially on the console.
But I am stuck on #20 - removing the dash itself. I have it all loose. I can raise it a couple inches, but it just doesn't come out.
Does anyone have a close up of the latches that have to come loose?

 

welcome

 

"welcome" - to what? heater core hell? (actually, that should be crying, not laughing).

Other times I've asked for help, I've gotten a pretty fast response. But nothing today.
This is getting me a bit nervous. Help!

 

Assuming this part is the same as on my 89. Get the part number for the plastic clip that is on the rod inside the heater box and replace it. Might as well while it's apart as the clip can break.

And yes, you'll need to pull the passenger carpet and clean it and under it. I've taken the carpet to the car wash and pressure washed it. Then used a carpet extractor back at home.

I also got some 3M strip caulk to pack around the heater tube holes where the heater core tubes pass through the firewall. I did have to do a test fit and slightly bend one tube to keep it from touching the firewall, as that could have eventually rubbed a hole into the tube. I also put a small piece of blue painters tape over the end of the tube when installing to keep the factory black sealant from getting in the tube.

Also, I had searched around the internet and found some people will pressure test the heater core first. I got some pressure tester pipe from Lowes and some heater hose and caps with hose clamps. And you clamp that and some rubber end caps to the heater core. And you can connect an air pump that you use to air up basket *****, and I filled the heater core with air up to I think 20 psi, as the pipe has a pressure gauge. But check what pressure it's supposed to go to as you don't want too much.

And then I filled up the bathtub with water and stick the heater core with pressure gauge into the water for several days to see if you get any air bubbles and keep an eye on the gauge to see if you lose any pressure. Mine tested fine over several days and so far hasn't leaked.

Also, get some high temp brake grease, the kind in the little packets at Autozone, and coat the heater core tubes before you put the heater hose on. As that will help reduce the pressure onto the core when putting on the heater hose, as some people have said they got a leak after putting on new heater hoses. That grease will also help you remove the hose in the future.

 

The work continues. I got one of those video inspection gadgets to see under the dash and to figure out how to release it. But I found out that you have to also know what you are looking at. So it is a cool gadget but it didn't help. BUT, while trying it I managed to get the drivers half loose and saw the clips. So it seems liked just pulling every which way works and I got it off. I will post some pics of the clips later for the next guy. Unfortunately, as warned, this is almost 30 year old plastic. I had the dash resting and one of the front plastic clips broke off. I guess I will have to layer on some epoxy glue to try to get it back in place so the dash doesn't shake (if I can get it all back together). OTHER SUGGESTIONS ARE VERY WELCOME.

The airbag came out easily enough. While I was waiting after disconnecting the battery to take out the airbag, I decided to take out he carpet. The hardest part was removing the seat. That should have been a pretty easy job. There are 2 bolt covers with plastic pins that I was trying to gently take out. Very lucky that I realizes the pin comes out first, then the washer loosens up to just pull out. (pics coming). So there are 4 bolts holding down the seat and they weren't budging. I didn't have a direct vertical line for the ratchet extender and used a small universal joint. But they were is so tight that the u-joint broke. So I had to get them off with a regular wrench and lots of 30 degree turns. But I found about 53 cents and an old driving range token to pay for the work. Since only the bottom carpet piece was wet with antifreeze, I was able to just focus on that remove that with only taking off the sill and door jam cover. I hope I can get if back under the side covers when I'm done.

So once I had the carpet out, I decided to power wash it. It started raining so my wife got a laugh at me power washing in the rain. I poured some detergent on the carpet and it took quite some time until the water ran clear. Now it is drying in my garage. I hope that worked else I'm going to have to get some sort of hand shampoo'er and start again.

QUESTION: the insulation under the carpet is soaked and I don't think that is salvageable but I am saving it as a guide. I only need that one piece. Suggestions?

With the rain getting harder, I decided to call it a day and will get to the heater core removal itself next.
BTW - recommended part? copper or aluminum? It's not an expensive part the price does vary widely.

Thanks all.

 

I've read people say an aluminum core could last longer the copper as they say copper core is more prone to corrosion. I went with aluminum, which is all everyone had at the time as there used to be a heater core shortage many years ago.

 

Did you replace the insulation under the carpet or did you wash that too?
If you replaced it, with what?

 

That material "jute" I had already replaced as I had a firewall leak from a shop with the previous owner apparently jacking it up wrong cracking floorboards and causing seams and pop rivets to loosen up letting lots of water come in. I had ordered something from a forum member who had new scraps of jute material. And I used the old piece as a template. I also cut off and taped on the bad spot on the tranny tunnel piece.

I didn't have jute damage from the later heater core leak as I caught it early as I could smell something when getting in and starting up the A/C, and then found it dripping some, but it didn't go through the backside. I went and got a "U" shape piece of heater hose and bypassed the heatercore until I could replace it. Go to eBay and look up "jute" padding. Some on there selling some. Just by enough so you don't have to tape pieces together.

Make sure to flush out the heater core with water before pulling so you don't get coolant dumped on removal. I used compress air to blow out the water.

 

Next steps... I installed the heater core bypass as I thought I was close enough to get the heater core out. But the steps for the 1995 with the glove compartment looks much easier than a 1996 with the airbag. I removed the lower bolts holding the heater core cover but it is still bolted down by something on the top. I removed a bolt from position A. I think position B shows the hot/cold slider that seems to be attached to the core cover and I think there is another bolt way up behind position C. It seems like I will have to remove the entire plastic vent that extends across width of the car!!! This seems crazy. Help!!!


Meanwhile, a couple helpful pics for the next guy.
I had a lot of difficulty getting the dash removed. In the end, it was just continually moving and pulling until it came off. Here's a pic of the tabs in the back that hold it in.


And here's a pic of the seat bolts cover pins:

 

(if anyone is trying to help, pls go to beginning of the previous post. This post is just informational for the next guy).
And, as warned in the instructions, be very careful removing any of the old plast parts. Here's a pic of a tab on the dash that broke off and that I had to layer in epoxy and I hope it holds when I have to put it back on:

 

Heater core is finally out! I second the motion to fire the engineering manager that approved this design.

Some help for the next guy:
In diagram above with the A, B & C circles.
B: my car has a manual hot/cold slider. This cable needs to be disconnected from the heater core cover by removing the black clip and the push on washer. I'm not sure what kind of wrap around pliers exists to pinch the tabs but I was able to do it by hand with some difficulty.
C: the hardest heater core cover bolt to get off. You need a bunch of extenders for the socket to reach in there. I was not able to remove the S shaped tube under the C mark which would have made it easier but I finally got it out. (Getting it back in has me worried!) In the video linked above, it said that he had to cut the S shaped tube to get the cover off. I was almost going to do that too but after wiggling it a bunch, the 3 inch extension tube that is attached to the S tube (on the left side) and goes through the heater cover came off and I was able to slide out the heater core cover.

Here's a pic of the heater core bracket :

Questions:
I'm wondering if it would have been easier if I removed the bolt circled in yellow holding the casing to the firewall?
What is the area (orange squiggly line) that the back of the heater core opens to? Does that go to the blower?
There's an orange vacuum line connected to a diaphragm (white oval). What is that?

Now going to order the replacement core and maybe a couple tools that will help put this back together.
I'm amazed at how many compatible heater cores I find online. Any specific recommendations?

Anything else I should be looking to do while this is all open?

 

Finally installed the new heater core. (thought doesn't seem to be anyone listening, so this is for the 'next guy')

I removed the top bracket that holds the top of the heater core in place (see yellow circle in pic) but it was impossible to get it back on after the heater was put in place. So I had to take the heater core out again, install the bracket BUT KEEP IT LOOSE, then install the heater core and tighten the bolts.
I'm going to drive it around for a few more days to make sure there are no leaks before I try to put everything back in place.

 

Nice work, I need to remove mine from an 86 so it's helpful even though some of it is different. Same dash clips, that part should be no problem.

 

Started the reconstruction. I put the heater core cover back on today. I bought this flexible extension on amazon for $8. Worked great. (see pic. label A)
Also, the pro tip on the video to tape the screw to the end of the extension socket was a necessary step to get these very difficult to reach screws back in.

Then there is the heater tube extension scoop that goes on the 1 inch tube that passes across the back of the heater core cover. (see pic. label B) This is the part that made it impossible for the guy in the video of this repair to remove the cover and he had to cut the tube. When I was jiggling things to remove the cover, this extender came off and I was able to take the cover off without cutting it but it is officially IMPOSSIBLE to put it back on without taking off the rear wheels (, I mean taking apart a ton more of the dash) so I left it off. I'll be driving it around like this a bit and we will see if I get airflow without this part. Else I will have to remove the cover again () and cut this tube to put it back in. Makes one question the brains of these engineers.

 

My son and I are in middle of replacing the heater core. I have run into the same issues as you. We have 1995 with manual blend door as well.

We were stuck at removing the blend door cable. I got the washer and the cable off. I could not get the outer cable to snap loose. I even tried at the controller side. I have not tried pliers.

I am soaking it over night with some silicone lubricant and going to try in the morning.

I appreciate the information!

Patrick

 

Ok, follow up for the next guy.

We were able to remove the cable for the blend door. It has 2 clips in the base. I used a small screw driver on clip closest to me pushing it toward the center and rocked that edge up. Then on the far side I couldn’t see I used a small screw driver to push that side to the center and was able to get it up.

We were able to get the new core in. The additional duct that snaps into the side window defrost duct and inserts into the heater duct is in position as well.

We disconnected the side window defrost duct on the passenger side where it snaps into the flexible portion.

We then positioned the cover over the heater core.

By pulling the side window defrost duct down and away while pushing the heater core cover up, there is enough room to slip the duct portion into the cross portion of the side window defrost duct at its base while the remaining portion is in the heater core cover. This is much easier if you coat the duct with silicone spray before.

From there, we connected the side window defrost duct back to the flexible portion of the passenger side window defrost duct.

You could not do this without the dash being removed. It adds a little work to pull the dash but it makes the job so much easier.


Hope it helps.