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Chevy1966

08-26-2017 03:28 PM

Firewall Sealant Mystery Stuff

1 Attachment(s)

Does anyone know what kind of spray on sealant GM used to seal the firewall around the heater box and other grommets? It's clearly something that was sprayed on but it is definitely fairly thick. Of course there are various sealant that will do the job, but I am trying to keep my engine compartment looking original. Thanks for any info!

Pine Bark Auto

08-30-2017 11:39 PM

Re: Firewall Sealant Mystery Stuff

3M Rubberized Spray undercoating (aerosol can) does a reasonably good job of mimicking that look.

wazzabie

09-01-2017 12:54 AM

Re: Firewall Sealant Mystery Stuff

Quote:

Originally Posted by Pine Bark Auto (Post 8028799)

3M Rubberized Spray undercoating (aerosol can) does a reasonably good job of mimicking that look.

There are several types of 3M underspray. Which do you recommend?

Pine Bark Auto

09-01-2017 04:15 PM

Re: Firewall Sealant Mystery Stuff

Found a can still in the shop. It says "3M Professional Grade Rubberized Undercoating" . The part # is 03584. I admit I have not bought any in some time and have not verified its current availability. It sprays on pretty thin and dries to a flat sheen.

ray_mcavoy

09-01-2017 04:54 PM

Re: Firewall Sealant Mystery Stuff

I used Evercoat #101348 rubberized undercoating to duplicate that factory sealer on the firewall of Dad's 77. I've found that the Evercoat brand undercoating seems to go on a little thicker than the 3M brand. But neither one of them is quite as thick as the factory stuff.

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