If you include the model year and engine size, you might get more help.
If it is a serpentine belt you replace the tensioner pulley
Remove the belt, then remove the bolt in the center of the spring tensioner with a 15mm wrench, install new one
No you can not, It is kept tight by a spring loaded belt tensioner with a smooth pulley on it. Probley needs a belt tensioner on it.
If you're standing at the front of the truck and looking into the engine compartment the tension pulley is on the left side about half way down.
It is the small pulley with a nut in the middle on the pulley assembly!
if by "loosen" you mean loosening the belt then just put a wrench on the nut in the center of the pulley and turn it to the left. its basically spring loaded.
I don't believe there is an idler pulley on that model, just a tensioner pulley
Pry bar.
The tensioner bolt for a 96 Cavalier is in the pulley for the tensioner. The tensioner is in the middle of the front of the engine.
You can change the serpentine belt by loosening the tensioner pulley. When the tensioner pulley is loose and the serpentine belt will become loose. Put the new serpentine belt on and tighten the tensioner pulley.
You can adjust the belt tensioner by loosening the tensioner bolt. When the tensioner bolt is loose the tensioner pulley can move back and fourth.
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