Yeah, my brother in-law who is body man told me about the 3M Seam Sealer when I had a bad leak near the rear hatch on my old Bronco II. It fixed it up real nice. Never leaked after that.
I never knew there were seams on an automobile that are not welded. On this Bronco the old seam sealer just hardened, then cracked, then fell out. Sealed up the cracks and it was fine. Good Stuff!