Getting ready to pit the tank back in wifey's 65 Belvedere wagon. I put the grommet on the tank and it is loose enough that it spins freely. I even put the filler tube in and I can spin the filler tube by hand. It's snug around the filler tube, just loose on the tank. Should I try some gasket sealer or urethane caulking or something so I don't get fumes?