| The cooling system has a pressure relief valve that is designed to prevent excessive pressure from damaging the hoses. Either the hose connection came apart (because it was loose) before the pressure relief valve lifted, or the valve is failed to lift at the proper pressure (and needs to be replaced.)
Either way, the repair's not a big deal.
If you're concerned about a blown head gasket heating and pressurizing the coolant, almost any auto shop can test the coolant for the presence of exhaust gases. |