Heater box sealer

[Joseph M.]

The factory apparently used a black tar like sealer around the heater box when leaks were detected. Do all cars have this sealer present and would there be a deduction during flight judging if it is not present? What product is being used to replicate this process? Thanks.

[Gene M.]

Re: Heater box sealer

Joe,
Gm only used it on "leakers". No deduct for not being a "leaker".

[Ara G.]

Re: Heater box sealer

Gene
I got a deduct at Kissimmee Regionals with my 390 car...I argued my point in a nice way that only the leakers got the "goop" treament, all to no avail...They wanted to see the sealant regardless...

[Gene M.]

Re: Heater box sealer

Sounds like some judges need to attend the advanced judging schools. Remember judges are just volunteers and make some calls that are incorrect.

[Mike E.]

Re: Heater box sealer

I took a couple of shots of a '65 in Bloomington that had the goop treatment. Not the best images but you get an idea how it looked...This car I think won best of show for a restored car.

Edit: I'm not sure this is correct...I would like to hear what other folks say.

[Harry S.]

Re: Heater box sealer

When I pulled mu 63 apart, there was no evidence of that black goop anywhere.

I agree, only the leaker's got it!

[Michael M.]

Re: Heater box sealer

From my research the material that was used to fix or detect leaks was sprayed on the heater box where it met the firewall. Note sure if the photos posted above look like the material was applied by spraying.

[John C.]

Re: Heater box sealer

I have to agree with Michael, it was sprayed or somehow poured on.

The attached picture shows the sealer applied on a 68.

John

[Mike E.]

Re: Heater box sealer

I don't disagree with you guys...The photos I posted may not be correct...It looked really strange to me too...I was interested in feedback. I will edit my original post to refect that.


Mike

[John H.]

Re: Heater box sealer

The Fourth Edition, Second Printing of the '67 JG (page 119) makes it quite clear that the material is a typical plant "leaker" fix and doesn't necessarily appear on all cars.

[Nick C.]

Re: Heater box sealer

How would an externally applied sealant prevent heater box water leaks? A ridiculous proposition at best, folly at worst.

Has anyone in this discussion considered that the externally applied material may have been intended to minimise offensive gaseous engine compartment vapor from entering the interior cabin, much like the sealant applied at other firewall to cabin gaps at the ballast resistor mounting hole, clutch boot, and other firewall to cabin openings?

[Mike E.]

Re: Heater box sealer

How would an externally applied sealant prevent heater core leaks? A ridiculous proposition at best, folly at worst.

I believe it wasn't to prevent heater core leaks..It was to prevent water from the engine compartment leaking into the cabin.


Mike

[Nick C.]

Re: Heater box sealer

Same theory, to isolate engine compartment from interior cabin.... I have not seen spraying water directly on the firewall as part of a water leak test in the AIM spec.

[Mike E.]

Re: Heater box sealer

I have a searchable PDF version of the '65 AIM...It does mention a sealant on page 227, I'm not sure this is the correct one.


I couldn't find anything in the AIM about a leak test either, other than the A/C system (Freon).

It's is documented in John's amazing Assembly Process document on page 22.

http://www.michiganncrs.org/index_assets/CorvetteAssyProcess.pdf

Edit: I searched for "Water" and turned up this in the AIM.



Mike

[Terry M.]

Re: Heater box sealer

Sounds like some judges need to attend the advanced judging schools. Remember judges are just volunteers and make some calls that are incorrect.

Gene, EVERY 1968-1972 (and I suspect other C3s as well) got the "goop" treatment, and the AIMs call out that sealant on the heater box, and sealant on the grommets where the speedometer, tachometer and oil pressure lines pass through the Instrument Panel. Are you sure that midyears were hit & miss?