redoing my taillights.... ???

when i put the smoked lenses on my 5.0 it came with this blacck stringy looking tar sealant that you stretch around the lights before you push them in place. make sure that you take your time and remove the old tarry material before you do this.

ps-silicon wont hurt either
 
3M makes a weatherstrip sealant- kind of like black RTV, i guess. it works alright. i dont know what was used originally. good luck.
 
89Sleeper is right. It is like a putty that comes in a roll. It is some kind of trim or window sealant. Shouldn't be too hard to find. I didn't use any when I polished and repainted the housings on my taillights and haven't had a problem with water, even with the 150% humidity and constant rainstorms here.