Is it really beneficial to keep? Can I close it off to prevent further rusting, or does it need to be open?... Is it part of the air conditioner? or just an open airflow port?

Thanks!

 

This is the pressurized inlet for the heater, air conditioner, defogger, and fresh air vents. The first three will function very poorly if you block it, and the fresh air won't work at all.

 

I am not sure about AC but it is used not only as a vent on the drivers side, but also is where you draw you air into your heater box on the passenger side.

 

So then the best thing to do would be to open it fix it, paint it with anti-rust paint stuff and then get those magnetic cowl covers for when it looks like it's gonna rain, eh?

 

I would say if you fix it right you won't need the cover. Most use those when it is rusted out so they don't get water in. Once fixed, it should last a long time.

 

Even a minimal amount of care would make it last indefinitely. The lower half of the cowl was not galvanized, rustproofed, or even painted, and they still lasted 5-10 years before they started rusting through.

 

As stated above it is required for the fresh air vent and the stock heater. You have 2 choices.
1. Fix the cowl. My suggestion here is to buy some stainless grill and weld or panel bond it inside the cowl below the vents. While water still gets in it'll keep out all but the smallest debris. If your really good you could get the stainless grill (or aluminum I guess), put some type of edging around it covering the sharp edges and then panel bond that on top.
2. Replace the stock heater & a/c with an aftermarket setup, remove the huge fresh air vent from under the drivers side and then panel bond some metal plates into the top of the vents. Bit of body fill, primer, paint and you'll have a nice smooth cowl.

I went with option 2. Ordered a Vintage Air setup, removed and closed off the fresh air vent (open/crack a window if you want fresh air) and bonded 2 pieces of stainless steel over the cowl vents.

 

Adrenolin, that's just what I wanted to hear! Thanks!