[Al Schober]

You don't say which end is stripped. From your description, I'd say the top end (nut to stud). If a new nut doesn't fix the issue, it's time for a new stud. Pull the old stud out of the block (leave head in place), run a tap into the block to clean the threads, then install a new stud with your sealant of choice (toss up whether I'd use Permatex brown stuff or JB Weld epoxy). Keep in mind that this isn't just a t'stat stud - it's also a head stud and has to be torqued to the same value as the other head studs.
Not a big deal.