On a 67 model year A/C car does anyone know what is the correct spec size o-ring seal goes in the groove of the base of the heater water valve to the bracket, or is the correct type seal something else (Viton, Teflon, other)? The only info I have found is on the Cougar forum someone used an o-ring of unspecified size, with a bead of orange RTV applied as well.
Thanks,
David