I finished a serpentine swap on my Monte this weekend and noticed something on the idler arm when trying to dertermine the correct belt length. There are some markings on top of the idler arm; I figured these markings are to determine if the arm is in the correct position with the belt installed. Anyone know if this is the case? If it is, what does the position of the markings need to be?

 

The idler should only go on in one position. There is a recess for the dowel on the idler in the mount. The marks just show how far the idler can be moved when replacing the belt.

 

Yes, those marks denote the high and low end of the tensioner's proper adjustment range. Get the mark on the main bracket to line up between the two lines on the tensioner's arm and you're where GM wants you to be.

 

Damon, thanks!! That's kinda what I figured, but wanted make sure. I think if I go with a 93.5" belt it'll put me right where I need to be.