V-Belts are critical for proper vehicle operation. You will want to replace the AC compressor belt and inspect your pulleys.
To get proper clearance to tighten the tensioner, put a 17mm socket on the plate followed by a long+flat wrench with a small extension (just enough to not to hit the fan, if you lack space take off the fan).
Put a spark plug socket on top of the wrench with an extension attached to give you more leverage.
From driver side, push the extension forward while using a smaller wrench to tighten up the bolt securing tensioner plate in place.
Two 13mm bolts for adjusting pulley/tensioner: 22 Nm