66 heater box sealer

[Danny L.]

Can anyone comment on what product (and source) to use as a sealer around the heater box on a 66? Originally, this was apparently some type of messy glue which was used to seal the heater box to the firewall. I am interested mostly in making it correct for judging purposes. Thanks.

[John D.]

Re: 66 heater box sealer

Danny, Dave Kitch and others covered this subject extensively about a year or so ago. Look in the archives. We used strip caulking and smoothed it out. Worked OK. Passed judging. John

[Danny L.]

Re: 66 heater box sealer

Thanks John. I will do some archive research as well.

[ed styczynski]

Re: 66 heater box sealer

I have a 65 and two years ago went through Bloomington judgeing - the judge we had said that the sealer was only put on at the factory if the box showed leakage. He said either way could be correct - since I lost no points I never looked into it. Mine has no sealer, looks like that may not be correct or possible.

[Eugene B.]

Re: 66 heater box sealer

Ed, et al.
When I restored the heater box on my original '65, I found no sealer present on the outside heater box.

The way the whole assembly is designed, it seems to me that if all of the inner seals are functional, any water that runs into the top of the outside heater box will simply run out the bottom. But I'm no expert. It's nice to know that 3M strip caulk will solve the problem it I experience leaks.

Best regards,
Gene

[Gary Schisler]

Re: 66 heater box sealer

Relying on memory, but the boxes were sealed with a tar-like substance that had dried out over the years. I think some folks have equated it to something similar to roofing tar that has been heated almost to running and then dribbling it along the seals. My 66 had this substance and it was tired and dried out. When I had to replace my heater core, I did a little searching and found that those who bothered to replace the it used either 3M strip caulk and some even used roofing tar.

Gary

[Dave K.]

Re: 66 heater box sealer

Actually, I used a black liquid sealer that was called GM windshiled sealer on my heater box. It is used to seal the rubber windshield gasket to the glass. As Gary reported, it is liquid but viscous almost like the consistency of liquid roof tar and it remains tacky for some time.

I did an inspection of mid year cars at the San Antonio National and saw that many had this type of sealer on the heater box.

As for judging points, I too had no sealer on my heater when I was judged at a chapter meet by two Master judges and lost one point for not being typical.

Dave K.