You did not mentioned the fan belt. That is the usual cause.
You don't. The pulley is pretensioned by the manufacturer. If the belt tension is incorrect, the pulley must be replaced.
There is no fixing it. It must be replaced.
No, tensioner pulley is at a preset tension, no adjustment can be made. If there is slop in the belt, the spring loaded tensioner should be replaced.
There is no way to adjust the belt tensioner, if it's not keeping enough tension on the belt the complete tensioner itself will need replaced.
Typically the o-rings can dry out and need to be replaced, the springs can loose tension and need to be replaced but nothing that can not be fixed
Seems to be pretty logical, doesn't it?
Check the tension on the belt. A power steering pump will whine if there is too much belt tension, putting pressure on the side of the pulley.
The tension spring is broken, and the entire assembly must be replaced.
You cannot adjust the tension on this, it has a spring inside of it. If it is weak, it must be replaced.
I have found using a socket with a racket wrench to be the easiest way to do it. When the tension is released the belt can be slipped off the tension pulley. The belt can be replaced the same way. Good luck.
Tension is accomplished with a belt tensioner, it is probably defective and needs replaced.
There is no adjustment. If it does not provide the correct tension it needs to be replaced. It is cheap and easy to do yourself from underneath.