Passenger side floor? Could be leaking heater core
freeze plug has blown out or leaking
that is your heater core. If it´s leaking inside the vehicle, your heater core is bad. The core itself is very inexpensive, but it cost a lot in labor to have somebody else do it.
Usually if it's not serious, check the cooling system hoses.
Check the heater core your water could be antifreeze leaking from it. Either broken connection where hoses connect or bad core itself located inside dash.
Most likely the water pump.
It could be that you have a leaking heater core, which resides inside your car. Another give-away for a leaking core would be a sweet smell inside the car and/or a sticky residue on the inside of your windshield.
If you have tried the raiator and the reservoir and hoses, you should have you intake gasket checked.
sounds like the water pump is leaking
inside the kick panel on passenger side
Antifreeze on the floor, windows fogging inside.
its inside the transmission remove the transmission pan and you will see it the filter snaps in
Most likely your heater core is leaking.