i had this strange noise like an exhaust rattle, intake or w/e and was at the dealer and they looked at it and the idler pulley bolt is loose. question is, do i need to replace it or does the pulley need to be replaced/re-tightened??? i have a new idler pulley in the box, so a bolt replacement would'nt be a big deal.

 

Are you talking about the stud and nut through the middle of the pulley, or the adjuster at the top. If its just the adjuster rattling around loose, give it a bit of a turn until it snugs up. When the stud and nut through the middle of the pulley is tight, there is no real load on the adjuster.

If the stud and nut through the middle of the pulley is loose, you need to adjust your belt and tighten the nut.

 

the adjuster on top is loose, do i want to lightly tighten it up by hand or with an allen wrench?

 

Lightly tighten it with a wrench or socket just to snug it up. Don't force anything.