The fan is electric, not belt driven. The serpentine belt is has a spring loaded tensioner. If the belt is loose, the tensioner has failed.
To fit a Vectra diesel 2.0 fan belt, make sure that you make reference to the user manual.
You can tighten a fan belt by tightening the tensioner pulley. Pry to the left on the tensioner pulley and tighten it.
Loosen the tensioner pulley. Put the fan belt around the pulleys. Pry the tensioner pulley to the right until the belt is tight. Tighten the tensioner pulley nut.
remove your fan shroud then losen the tensioner and remove your belt.
If it is a serpentine belt you replace the tensioner pulley
with the automatic belt tensioner..
There is no adjustment you can do. It has an automatic self adjusting belt tensioner. If the belt seems to loose you may need to replace the tensioner and belt.
Take off fan shroud and fan. Loosen belt tensioner. When you take of belt remember how it went on and just replace.
Put your new fan belt around the pulleys of your 1992 Chevy Blazer. Tighten the fan belt with the tensioner pulley.
first u must loosen bolt on power steering belt tensioner till the belt will come off ,then loosen alternator bolts and push alternater till belt is loose enough,then take fan belt off ,install new fan belt,use crowbar on alternator to tighten fan belt,then put power steering belt back on and tighten tensioner till its at spec. then retighteh tensioner center bolt.
The belt has an automatic spring tensioner and can not be "tightened".