I found my 1996 SE flooded two days ago ;(((. The carpet was dump on the passenger side. I lifted off the carpet and the sponge underlining was all soaked and there was an inch of water on the floor. I started pouring some water over the passenger side. I poured a couple of glasses in to the front holes and there it was... a little paddle accumulating in the very front right side of the front passenger well (the spot was the lowest spot in the car so it is irrelevant). It was hard to tell where it was coming from exactly. I also noticed that when I pour water in the left drain hole it comes out from one spot behind the left wheel and when I pour it in the right hole it comes out all over the area behind the right wheel.

Can anyone suggest me how I can trace this leak? I don't see any way of getting to that drain line. Does anyone know where in the FSM the drain system is described? And where are those drains behind the rear wheels are coming from?
Any help is greatly appreciated.

 

Tubes are located under the headliner and runs into the A-piller. Make sure it's connected at the top of the sunroof.

 

Heater core leak most likely.

 

Wouldn't it leak coolant in this case?