Heater core leaking

The hoses have to be connected in front of the firewall so you can access the hose clamps. That means the hoses do not go inside the car. If they develop a leak, the coolant will drip outside the passenger compartment.

Coolant on the floor comes from a leaking heater core.

In most cases the leaking inside the vehicle is a heater core. On these older vehicles that is not always the case. A lot of times people will not be able to find replacement parts or they are too expensive so they just use a heater core or other part that will fit and then rig it up to work. This means they could run the lines into the housing and connect the heater core when most connections of the heater core is made out in the engine bay.

This just means you are going to need to see if you have hard lines coming out from the HVAC housing in the engine bay. If they are not, then you will need to pull it apart and look. Either way you will need to pull it apart but at least you will have an idea going into it if the heater core is definitely the issue or it could just be a connection made inside the housing.

Let me know if you have questions. Thanks