Is this leaking between the lens and the frame or the lid and the
deck?
I just recently needed to re-seal one of mine, I proceeded thusly.
With the hatch closed and dogged, take a box knife and slice out all of the old sealant from around the lens, if cut both around the perimeter of the lens and the perimeter of the frame the sealant will mostly just
lift out.
Clean generously the groove, especially in the area where the lens was leaking with rubbing alcohol. Scrape the groove with a screwdriver and clean it again. Then once you think it's spotless, clean it two more times.
Lay masking tape around the perimeter of the lens and the perimeter of the frame, you should have left a
canal with masking tape on both sides.
Fill said
canal with ge 2800 or dow 785. These are both structural glazing silicones, available online for inexpensive
purchase. Standard home store silicone will work for a short time as well, but how often do you want to do this?
Lay a bead, wipe it smooth with your finger and walk away and let the goo cure.