Serious interior water leak

[Chillin014]

wow. thank you everybody for the suggestions. I am going to check out the heater box situation first since I did in fact replace the heater core a few years ago. I thought I did a good job sealing it up though but I will definitely check out all those areas.

thanks again.

 

[Chillin014]

I'm happy to report that I have found my leak. It turns out that the picture posted of the hole in my original post is in fact the source. The other side of this hole is not just a flat firewall, it is actually the lowest spot in the a/c box compartment where all the water is routed to exit a small flapping door. When pouring water on the windshield it came streaming through this hole. Now it is obvious how the whole floorboard was filling up with gallons of water with the car simply sitting in the rain.

I haven't decided how to plug it, but it shouldn't be complicated. Perhaps just some seam sealer or caulk.