C3 Firewall Heater Box Restore

[Jack O.]

I pulled my heater box from the firewall and found that it is selaed with a grey putty substance. Is this the way the factory sealed the boxes at the firewall? If so, any suggestion on the best way to put this back together such that it appears original? I'm using a foam seal and have cleaned up the box and firewall removing most of the grey putty but would like to have a factory appearance when complete.
Thanks.

[Joe L.]

Re: C3 Firewall Heater Box Restore

Jack-----

Yes, that's how they did it. Similar sealing material is available in some hardware stores as "3M Strip Caulk". It may or may not be part of Dr. Rebuild's heater box seal kits.

[Jack O.]

Re: C3 Firewall Heater Box Restore

Thanks Joe. Did it get pressed out to form a rather sloppy bead around the box?

[Joe L.]

Addendum

Jack-----

Checking out the Doc's catalog, it looks like he supplies a die cut seal for the outer heater box sealing. Personally, I would MUCH rather use this type of seal than any "strip caulk" type seal. I suppose if one is after every nuance of original detail, the "strip caulk" sealer might best serve one's purpose. In terms of functionality, I think that the die cut seal would be FAR better (and, give a much neater final installation). Actually, I just noticed this as a result of your question. The next time I have the heater box out, I'm going to use this die-cut seal. DEFINITELY.

To let folks know my philosophy: I am a big fan of originality. However, it's NOT a "religion" with me. If I can improve performance/functionality with little or no apparent degradation to originality, I'll do it most every time. The only exception to this philosophy would be for a "trailer-queen" type car. For such a car, performance and functionality are secondary and absolute, original configuration primary. I would never want to own such a car, of course, so that sort of situation would be moot as far as I'm concerned.

[Joe L.]

Re: C3 Firewall Heater Box Restore

Jack-----

Yes, it ABSOLUTELY DID. GM used a "semi-solid" sealer which never hardens. Strip caulk is about the same. See my "addendum" post.

[Jack O.]

Re: Addendum

I agree and since this is NOT a trailer queen, I'm going to make it look good and be sure it's sealed. I was and am going to use the foam seal supplied with the Dr. Rebuild kit but was debating on whether or not to add the extra goop just for appearance (in this case, bad appearance) sake. Thanks again.

[Geoff C.]

[bruce11495]

Re: C3 Firewall Heater Box Restore

There is a product used in the window business for sealing glass, not auto glass. Go to a supplier and ask them about it. The product name escapes me right now. I have a tube tucked away in storage, but it's not readily accessable. The product come in a variety of colours, black, grey, its a synthetic, works great, REAL hard to tell from original after road dust, oil and antifreeze.
Hope that helps, email me if you have more questions. Bruce