passenger side leak

i have a 74 mav. there is a leak on the passenger side which created a big rust spot on that area. i thought it was the heater core. so i replaced that and it only helped a little bit(the heater was bad any way). now im about to put new carpet in but im trying to find out were the leak is before i do. it is leaking right at the firewall. if you could help me in anyway that would be greatfull

 

Sounds like your cowl could be leaking. Pour some water in the vents, at the base of the windshield, and see if it runs inside the car.

 

thanks thats what i thought just didn't have time with school

 

it may be your front cowl / air vent tant the water hose and put water down your front vent (in front of your windshield) but don't let it flood out just do it as if it is raining out side but (don't let the windshield get wet) then after a few min look in the car to see if it is leaking if not then wet the windshield and see if it starts to leak

 

My 72 is leaking at the windshield gasket so check there also. It is all cracked and dry rotted
clint

 

My 72 also leaked at the windshield gasket.