jpc647

I was at work the other day and swear I found a thread with 'instructions' for replacing a heater core in an A-body Cutlass. It talked about how it was miles easier in a car without AC, etc. etc.

I can't seem to find it. Anyone know the thread? Anyone able to give insight as to how hard it is? Actual number of bolts and approx. locations to be able remove everything necessary? It'd like to not find out the hard was I missed a bolt and turn this into a huge expense.

Car is a 1972 Cutlass.

therobski

May depend on the year? Some are easier than others.

jpc647

True. Didn't think of that. Car is a 1972 Cutlass. Edited OP.

jpc647

I finally got everything out. What a major pain. Someone at Oldsmobile had their head up their a** when they design this. There's no reason I should have to take the inner fender out, but I digress.

The new heater core, albeit looks similar, is quite different. It doesn't have the crimped end tube, and it's make out of aluminum so it's quite a bit light. Like scary light. It's by spectre. I'm a little nervous using this. I thought about having the original fixed, but I don't see an obvious problem and if it gets fixed in spot a, how long before spot b starts leaking. I don't want to do this again in 1000 miles. Or ever again, for that matter.

20151004_183457_zpsbinx9eut.jpg

Secondly, the blower motor is making noise as of lately. I figured there was a leaf or something in it, but it appears it's the bearing in the motor. Great, gotta replace this too. Any one re-painted the heater box? What brand satin finish did you use?

It's not awful, but while it's out, it probably should be painted. Might as well.
20151004_183625_zps8fvuekh6.jpg

Now so I seal the heater box to the firewall with some kind of gasket material? What should I use?

On the inside of the box there is the flap door for heat, and the rubber gasket is all deteriorated and crappy. What should I use in there? Or just put it back? I was thinking some sort of stick on foam gasket, similar to whats used around like storm doors, but wasn't sure if there was something better?
20151004_183509_zpsb3fwrfao.jpg

The vent tube under the dash is all brittle and old, can I just use the same OD tube that is used in HVAC systems. It's bright colored, but it's under the dash, and is probably better than the 40 year old stuff, right?


And then there's the inner fender well, it's out so I should fix that. Which is going to turn into doing both of them. All this for a tiny little leak on the passenger floor. I've heard easy off and mothers back to black. The easy off scares me, I don't want it to tarnish or fade the black plastic inner fender.

Weathertech mats and a heater core bypass seem like a good investment, in retrospec. Ha, I'm kidding. Kind of.

oldcutlass

The nice part is you wont have to redo it again for another 30 years hopefully. Any satin black will work fine. When you do one wheel well the other will stick out like a sore thumb. Be careful of the MAW's.

jpc647

Thanks.

What about inside the box, where it looks like the gasket material is all peeling and falling apart. How do I replace this? I was thinking using like a stick on adhesive backed gasket, like you would put around a door. But I'm worried the door then won't seal.

oldcutlass

I didn't worry about the door on mine. Just basically did a light cleaning, dropped the heater core in and secured with the hold down plate. The reassembly is easier with 2 people to get the box mounted back on the firewall.

jpc647

Okay. I guess all I have to decide on is if it's worth it to try and add and sound deadening up on that side of the dash, and try and find one of the retaining nuts that I lost and replace. And cross my fingers that it don't leak.

jpc647

Ran into another problem. The old copper core has a lip on the end tanks where the factory bracket clips into and holds the car. The new aluminum tank is rounded so the clip has nothing to hold onto. Anyone else run into this?

Also, it looks like there was some sealant or chalking on the edge where the heater core sits, almost like a vibration stop. I should probably use some sort of adhesive pad there when I replace it?

Fun71

First time I changed the heater core back in the early 80s I left that one bolt out so I would never have to deal with it again, and I am extremely glad I did that.

oldcutlass

jpc647

Ha. that's not a bad idea! Did you ever notice a rattle or anything? Leaving that one bolt out in the heater blower motor cover is ingenious. I'm definitely going to do that!

Ran into another problem. The old copper core has a lip on the end tanks where the factory bracket clips into and holds the car. The new aluminum tank is rounded so the clip has nothing to hold onto. Anyone else run into this?

Mine was just a tabbed spring clip that bolted in and held the core in place.

Also, it looks like there was some sealant or chalking on the edge where the heater core sits, almost like a vibration stop. I should probably use some sort of adhesive pad there when I replace it?

You can ad some high temp rtv to keep it from getting chaffed.

I'll attach a photo tonight, my spring style clip has a lip on it. Maybe someone can shed some light on it then.

But thanks for the high temp idea. That's a good idea. A nice bid bead of rtv should be enough, then I'll rtv the box to the firewall too.

oldcutlass

I wouldn't rtv the box, it does not need to be 100% airtight.

jpc647

Really? There was some sort of sealant when I removed it from the car?


If you look closely you can see the clip has a curled edge to grab the lip, but the new core has no lip.
20151027_170801_zpsqvmdrhc7.jpg

So the bracket sticks up too high.
http://s478.photobucket.com/user/jpc...layhr.jpg.html

And it's def. in the right way because the other side bracket lines up with it's slow.
20151027_170819_zpsgugtjju2.jpg

oldcutlass

Aren't there screws that hold the bracket in place? The box is going to seat on the insulation and some padding. You just want the core to be snug and not rattle around.

jpc647

Yes, there are screws, but the bracket doesn't sit flush because of the difference in the core.

Notice picture 2. There is a little curl at the bottom of the clip where it meets the core, it needs to clip onto the core and pop into place.

oldcutlass

The clip in picture 2 just needs to be adjusted so it doesn't stick out. Between that clip and the clip on the opposite end I don't believe the core is going any where.

jpc647

Okay. Fair enough. I know I could bend the tab to go around, but I tend to be very cautious modifying parts, not a big deal in this case I suppose.

Thanks for the help.

jpc647

Anyone know how the defroster adapter goes back? Obviously the hoses connect to the plastic tubes up under the dash, but I can't seem to figure out the actual adapter, where it bolts to, etc.

Stupid question, I know.

20151031_181325_zpstnkdi3py.jpg

Fun71

It just slips on, the metal tabs hook into the main box to hold it, then one sheet metal type screw holds it to the box.

jpc647

Thanks. I just seemed strange it just sits in there.

I guess I should have put that adapter back in place before the box went in. Damn... Live and learn...

This should be fun.

jpc647

One last question, more for reference I guess, but thheres a cable that mounts on the left side of the box. It's called an Air Valve.

What does it do? The clip broke, and I was going to make something else work, but it doesn't connect to any switches on the dash. What does it do? I can't seem to get it stay all the way to the left, it just bounds back to the right.

oldcutlass

The cables are operated by the selectors on the dash. Warm/cool/ defrost.

jpc647

Thanks for the photo. It was getting dark, maybe I'm just missing it, but the two lines from the control panel you showed are already connected to the box. One at the far end by the heater core, and one closer to the middle.

This one is on the far left, I couldn't feel where it goes up to the dash. But the pages from the Service Manual call it a Air Valve.

oldcutlass

Not familiar with your setup, but it may be a fresh air vent. Mine are in the kick panels. Follow the cable to where it starts.