3M Automotive 8610 Window-Weld Round Ribbon Sealer, 1/4" x 15'

I've used this product to reseal the tail lamp buckets of my vehicle, worked very well. The original factory sealant had shrunk but also hadn't been applied correctly at the factory which allowed some water and dirt to get behind the tail lamps into the body cavity. Tip: apply the material to the body close to the edge of the opening in the body panel, then reinstall the tail lamp bucket and press down so the sealant can stick to the bucket for a good seal. Remove the old sealant from the buck and body panel first of course. A mild paint safe solvent works well to remove the old sealant (which is likely a very similar product to the Windo-Weld)

Great product, good price when purchased. Worked perfectly sealing an evaporator/heater core box