Most likely it's a ruptured heater core, leaking coolant.
But before you replace the heater core, check the connections outside the firewall. Sometimes a leaky connection will drip to the inside... but don't expect it; it doesn't happen often.
rear freeze plugs
Radiator or hose but probably water pump
leaking heater core
Match the color of your antifreeze to the new one you buy unless it states its good for all types.
You are experiencing the classic symptom of a leaking heater core. They aren't cheap. Some stop-leak in the radiator might get you through the interim if you need to budget it.
The water leak could be caused by a damaged or clogged HVAC drain tube, resulting in water accumulating in the floorboard. Check the drain tube for blockages and clean if needed. It's also possible that the weather seals around the doors or windows may need to be checked for leaks.
engine diagram for a 1993 saturn
Regular antifreeze such as, green, or red!
There is a heater hose that goes in the left rear back side of the intake manifold that hooks to a quick disconnect fitting, It is common for the fitting to leak antifreeze. If it is oil that is leaking, then there is a oil sending unit to the right of the distributor that could be leaking oil. There is a long rubber gasket that seals the back of the intake manifold to keep it from leaking oil also. That's all that could be leaking back there. GOOD LUCK.
1993 Saturn sl2
Green
i have a 1993 saturn sc1.the relays in the sunroof keep the sunroof from working.anyway to fix it