'73 Heater Core Removal

[Jerry Britsch]

I have a '73 non airconditioned coupe that has a leaking heater core. I have removed the right dash pad, instrument cluster, center console and the 4 nuts on the engine side of the firewall. The heater box won't budge however and I'm afraid to get rough with it by pulling too hard.

I would appreciate any comments on how to remove the heater box and any other tricks concerning the heater core replacement. Thanks.

[Joe L.]

Re: '73 Heater Core Removal

Jerry-----

It sounds like you've got all of the hard work already done. I expect that the problem is that the heater box has been "married" to the bulkhead for so long that it's "stuck". As I recall, the first time I did mine it was like this, too.

First thing that you should do is to look all around the box to make sure that there still isn't something "permanent" holding it in. However, if you've removed the 4 nuts from the engine compartment side of the firewall, that, as I recall, should do it.

I'd try applying moderate but constant pressure to the upper and lower surface of the box to see if you can break it free.

Once you get the box out, changing the heater core is very easy. There is a retainer with, as I recall, a single bolt attachment which holds the heater core into the box. Remove it and pull out the core. One thing, though: replacement heater cores, including GM/Delco, are configured a little bit differently than the originals. You may have to slightly modify the inside of the box or the retainer to get the new one to fit properly. So, don't be surprised if this is the way it turns out.

[Jerry Britsch]

Re: '73 Heater Core Removal

Thanks for the response Joe. If pulling on the heater box doesn't get it loose, I thought about tapping on the studs on the engine side of the firewall using a wood block and hammer.

[Paul L.]

Re: '73 Heater Core Removal

I took the heater core out from the firewall side.

[John Walker]

Re: '73 Heater Core Removal

Jerry; be very careful, I found more nuts under the box on the engine side of the firewall. So, there were nuts on the firewall side then I removed the box that surounds the heater hoses and there were more nuts on the studs then the box on the inside came out easily, as mentioned before the core is held in the inside box and it is easy to work on on the bench. John

[Jerry Britsch]

Re: '73 Heater Core Removal

Paul, thanks for the photo. Is this from a '73?

[Paul L.]

Re: '73 Heater Core Removal

No it a job I had to do twice on my 1979 L-82. I was under the impression that all non-A/C C3s could be done through the firewall. It's a one-hour project. The trick as noted by Joe is to get a replacement core that is the correct size as some generic Chevrolet cores are a wee bit larger and will not fit through the opening.