The cowl is the "grid" between the windshield wipers and the hood.
When working correctly, the water goes out the sides. If you have a 67/68, its where the mustang and engine badge decals are. This is on the fender, just in front of the doors.
When working incorrectly, the water will go inside the car. Where your feet are.
Use a large bucket of water or a hose.
The setup (that you cannot see) is that there is a stove pipe type thing in there. Say you had a flat piece of wood, and cut a hole in it, and then put a piece of stove pipe over the hole.
The theory is that this allows fresh air into the hole, but not water.
The mustang "stove pipes" were NOT prepped very well at the factory. Thus they rust where the stove pipe meets the flat piece of wood (in the example above). And now water runs straight in.
The odds are VERY LIKELY you have this problem.
My second (65) mustang, I reached up in the heater box (passenger side, where your feet are) and reached up there and pulled out the rusted up stove pipe piece. Which means any water coming into the "grid", eventually comes straight into the car.
This is a MUST fix it project. You can get Cowl Covers to cover the grid. This in my opinion is better than nothing, but not the permanent fix. They are like $30 or so.
Do a search for "COWL Repair" (an AND search) and you'll find TONS of info.
- My Original Mustang Floorpans || My (new) 1977 Granada
- My 68 Mustang