No heat in Roadmaster

GM, used (and probably still does) use sealing tablets on new cars, but they used them long before the Dex-Cool came around in '96. The issue with the orange stuff was it's incompatibility with the intake gasket material GM was using. They fixed that in '02 or so. LT1 engines never had the issues the rest of the the GM line had because coolant doesn't flow through the intake.

Mike