serpentine belt tension - how tight?

[Fasterblaster]

I pulled out the alternator of my 2003 200 Select with the 5.0 MPI. I think i have correctly routed the serp belt ( I taped it up with duct tape, but it feel off and know i'm guessing). How much deflection should i look for when i tighten it up. I'm thinking 1/2-3/4".

 

[Turtlesboat]

1/2 is about right. if it's too loose, you'll probably hear it squeal.

 

[topgun1185]

serpentine belt tension

According to the merc book there should be no more than 1/4 inch at the longest span between pullys.