So I noticed this last night after I washed my truck: http://imgur.com/AygiVv9

That's a picture of the seam in the upper left windshield area. There are no obvious holes on the roof above so I'm not sure what to do about it. Is it something I should go to a body shop about?

 

For some reason I couldn't open your pic but you are describing a common rust area. If so then yes take it to a body shop.

 

 

Thanks Gembone.

**I meant right side not left.

 

Assuming its not a show truck, and the rust isn't too bad, I would remove the windshield and gasket, scrape and wire brush out the dried seam sealer and loose rust, treat the metal with OSPHO (being careful not to damage the interior), clean it well with lacquer thinner, apply new seam sealer and smooth it for the gasket fit, apply touch up paint, and reinstall the windshield with a new gasket and windshield sealer.

Do the same for any other area that looks like that.

 

The roofs of bumps and dents are uninsulated. Warm air trapped inside with a cool outdoor temperature results in condensation forming on the underside of the roof which then, after forming enough dew, will make its way to the roof rails and lead to rust from the inside out. This leads to roof rail rust. Traces of the corrosion can also manifest inside the cab as show in the pic above.

It's the same principle as a cold beer on a warm day.

If caught in time, insulating every nook and cranny of the roof as to mediate the temperature swings and air circulation can stave off the corrosion.

 

How would one go about insulating the roof?

 

Some have used fiberglass batt household insulation to stuff the front, sides, and back. Some have used expanding polyurethane foam.

The open areas? Automotive insulation like this: Aluminized Heat and Noise Insulation Shield, 2-Ply - Speedway Motors, America's Oldest Speed Shop

 

Ford spot welded the individual drip rails to the roof, then used paintable caulk to smooth and fill in the gaps. Caulk chips off, water seeps in, drip rails begin to rust, soon spreads into the roof.

 

More often than not, roof rail rust starts on the inside and works its way out.