radman
R.I.P. Our Motorcycling Friend
Unlikely, as hose connections are outside the heater plenum where the core resides, generally they connect at the firewall. Can't find the new miracle sealer, at least until Saturday, when I will talk with my source. I have had good luck with Bars Leak, better luck with Gunk Solder Seal, as pictured-Could just be a hose loose or split.
Often, is a permanent repair, most new cars carry a similar sealer from the factory. Be aware-any coolant system service like a flush and fill will require a re-ap.