Heater box to firewall sealer?

[DirtyLarry]

So, the heater core started leaking this past summer and I finally got around to replacing it a few weeks ago but it continued to leak antifreeze on garage floor even after the new heater core was installed. I figured it the problem was the Vhatozone heater core so I grabbed another new one from Napa and went to install it tonight only to find the Vhatozone heater core was not leaking after all but rather the heater box had a lot of coolant in it from when the original heater core was leaking.

Long story short, I pulled the heater box from the firewall to clean it up (what a pain in the a$$ on an A/C cab by the way!) but now need to find something to use to seal the heater box to the fire wall. I looked through the LMC catalog and didn’t see anything. I also surfed Lowe’s website to see what they have for rope dope.

Any suggestions???

[asphaltburner]

Yo!
I've always used plumber's putty. You know. for sealing drains to sinks, etc,...is that "rope dope"? Works great, it's cheap, and lasts! Not sure where I learned that,...it'd be a long time ago.
Just "roll" out a long thin "rope" in your hands, and press in place. Smooth with a finger tip. Seals nicely, but easily removed if needed. Todd.

[BLE 'BURBAN]

Go to a Glass shop and get a roll of small diameter byutile tape for windshields. I believe the smallest diameter is 3/16" or 1/4" Stuff works like a charm!!!

[DirtyLarry]

Thanks guys…

Well, I finally did find this product called finger rope caulk on Lowes website. I’ll go check it out tomorrow as it sounds pretty much like the stuff you guys are talking about.

[Walts_restoration]

ive got a box of what the factory actually used, used in on my 77, but man was it a PITA to install.

If you want a picture of the box, or what its called, ill find it.

[smashingchuck]

I know it might be kind of crude but why not use good old silicone?

[DirtyLarry]

I finally found the right stuff at Napa and basically what the OEM material was. It is a 3M product called Strip-Calk. I supposed one could use a lot of regular caulking at smashingcluck stated but this material never hardens and the greasy waxy material repeals water much better.

Hope to have time to put the heater box back together some evening this week. I am anxious to take for a test drive as I haven’t driven it yet since converting it from a frame mounted electric pump to a Corvette in-tank electric fuel pump and rigging up a transfer pump to run both tanks behind the 8.1L.

[Walts_restoration]

strip chalk, yup thats the stuff. Real pita when i did mine, dont know if i was doing it right.

[DirtyLarry]

What a bag of worms……If the evaporator doesn’t spring a leak by the time I am done it will be a miracle.

[DirtyLarry]

That 3M Strip-Calk stuff works nice. The A/C still works too so I got lucky there.




Better than new now…well, maybe.


Also relocated the Hi-Lift jack to the roof while I had some spare time. The last time I got stuck had me wishing it wasn’t buried under the sleeping platform. Problem solved.

[boatpuller]

i remember some of those bottom nut's.

[asphaltburner]

Yo! Guys!
The only problem with the old butyl stuff is that heat will make it run, and it's a REAL PITA to clean away if you need to do it again at some other point. The older trucks were done with a product just like plumber's putty. And it's ridiculously cheap,...I bought a 14 oz tub at ACE Hardware for $1.99, did two sinks, my Camaro's box, and my P/U's box, and still have about 10 oz left over (for more plumbing applications!). Remember it for the future. Also looks identical to OEM (on the '73's through '78s for sure,...newer trucks I cannot attest to), yellowish-off white. Just like what I scraped off of my '76 Camaro, '73 flatbed, and '78 P/U. And cleans off your fingers and firewall with just a wipe or scrape. Rolls into long strips for sealing easily between your flattened hands. Waterproof and never dries, remains flexible. Todd.