I am trying to seal the gutter area where the roof and sides meet on a 1988 GMC van, especially the area above the windshield. I’ve removed the old sealant, and found small rusted areas where I assumed the leaks were. I cleaned and primed the gutter, and applied the black Eastwood seam sealer. It seems to work for a week or two, and the leaks return. Is there a better product to use for this exterior application, or some other step to applying it to make it work? Thank you very much. :confused: