Well my Subaru spit out an idler pulley the other day. Its a 2001 H6 model and had been making a sound that I knew meant a bearing was going out in the belt system. Luckily it was just the idler and not an alternator bearing. I picked up a new bearing for about 50$ at the local dealership and also a 2nd one for the tensioner since I was in there. Simple matter to change em
Remove cover 4x 10mm
remove pulleys 2x 14mm
Put on new belt following path of old belt
Loosens tensioner and slip belt over tensioner and your done.
Mine actually destroyed the belt before I got around to it so I also had 36$ for a belt from NAPA.
And that’s it.