antifreeze on the passenger side BACK floor board , no where else can't figure that out?

Park on an incline?

Heater core leaking there is a small radiator under the dash for your climate control in the car. It is leaking and running back. Now depending on the volume of the leak here are a couple of stop gap solution for a temporary fix. The first one is ground pepper added to the radiator. The other is Bars leaks sold at the parts store. Both do the same things they send small particles through the motor to the leak site an block the flow. The bars Leaks uses aluminum. Now most modern Ford vehicles lose the heater controls with Bars Leaks for some reason.

You've got a leak in your heater core. When you use your heater engine coolant is routed through a fin/tube heat exchanger that is located on the passenger side. You might try a product called Stop Leak for radiators. There's a chance that it may work. Only other option is changing the heater core...and that's probably not to easy depending on the vehicle you have.

Good luck!

Just noticed BACK floor board. Do you have a heater between the seats in the back??

back seet floor board? that's odd. check under the dash to see if a trail of anti-freeze is originating there from your heater core. don't use any stop leak, that stuff will only cause problems. a heater core isn't a big repair.

Heater core leak, but it should get in your car because it has a drain, unless it's clogged, but WHY the back floor board.

Are you sure it isn't water. May have leaked in during rain?

it only can come from your radiator so it could be a hose or a hole in your radiator or someone could have spilled some?

its you heater core

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