Seam sealer questions

The windshield gasket will leak if the windshield channel drains are clogged . Using windshield sealer at these 2 drain holes causes the channel to over flow.

Also the cowl water dams do rust out. They can be repaired with rust neutralizer and then flex seal or POR15 putty from the top if you remove the vent box and heater core from the inside and go through the top of the hole to do the repair.

You must reach in on top through the hole and vacuum out the area and the rust proof it . I attached a small U-bent tube to a shop vac hose Then seal it reaching through the hole again. Here is where they rust.

If your cowl was filled with debris more then likely your windshield drains are clogged also.

But this is common for cars to rust in this cowl area. They never had any paint under the cowl. Debris just helps hold the moisture, Easy fix without removing the cowl from the inside if you take your time and use the correct materials it won't return in your lifetime. I did several . This car I removed the cowl due to it being damage from the vents being destroyed mounting of a fuel pressure gauge which allowed for these pictures .