Leak in heater core
A damaged heater core will cause coolant or water to leak onto the passenger floorboard.
Have the coolant system pressure tested, the pressure test will increase the coolant leak.
locate the AC drain tube on the passenger side firewall ( low )and clean it out with a piece of wire, water should come out when the blockage is moved. Of course it could be your heater core in which case the leak would be coolant and you will need to replace the heater core. you can connect the two hoses going into the heater core which are also on the passenger side firewall to stop the leaking while you wait for the part.
A poor seal or a split.
If that water is engine coolant, the heater core is leaking.
If you see coolant Inside the vehicle on the passenger side, The Heater Core would be the problem.If the leak is out side and you see a puddle on the ground below the engine from the passenger side, It can be a Water pump, Heater hose, Over flow from the Reservoir tank, or an intake manifold gasket.If the leak is more underneath the vehicle on the passenger side, It might be a Heater Hose and/or Heater Pipe which supplies the rear heater with coolant (if the vehicle is equipped with rear heat) .
Yes, it could come out of the ac drain on the passenger side.Yes, it could come out of the ac drain on the passenger side.
Lower passenger side of the firewall.Lower passenger side of the firewall.
Lower passenger side of the firewall.Lower passenger side of the firewall.
Passenger side of the firewall.Passenger side of the firewall.
On the passenger side of firewall, above passenger side of engine.