Old Ford truck's rain gutter sealant?

The roof of my 45 year old Ford truck has a little rain gutter all the way around. Sort of a L-channel tacked on to the edge of the roof, forming a U shape along with the edge of the roof. In the bottom of the U Ford put in some kind of sealant, presumably to prevent the rain gutter from rusting. That sealant is now deteriorating and the rain gutter has sprouted a couple of leaks which I need to fix before the rainy season. Any recommendation for products to renew that sealant? What’s in there originally from Ford is a very hard sealant of some kind, maybe body seam sealer? I’ve tired a couple varieties of caulk, which stops the leaks, but the caulk for some reason attracts dirt and creates an unsightly ring around the roof visual effect.

Any parts store that sells auto paint supplies will have this.

Tester

Got to trust tester, I have to wonder if there is rust involved.

Oh there be rust. But at nearly 50 years old, and having lived over 10 years in Colorado snow and road salt country, anything that’s not rusting is a surprise :wink: Fortunately it’s been away from the snow and road salt since I moved to San Jose. Overall the body is in pretty good shape for a truck that old, but eventually I’ll have to do some proper repairs on the rusted sections. In actuality it really needs to have a body off restoration and a new 2-pack paint job to look brand new. But I doubt that’s gonna happen. I was able to do a sort-of-proper rust repair and paint touch up on a rusted side marker lamp fixture earlier in the summer, so that’s looking in pretty good shape for the winter anyway.