what does it mean when the lines freeze from not enough antifreeze? on 1997 Mercury Mystique

ok so my fiancee and I thawed out the lines using space heaters and a tarp and then a whole lot of brownish red fluid came gushing out from somewhere under the car, what could the problem be?

Asked by for the 1997 Mercury Mystique
the cooling system needs attention,sounds like poss broken heater hose. repair coolant leak,flush entire cooling system and repl with plenty of anti freeze