Hi,
The bolts all need to be tight. Take a look at the pic below. I circled three bolts with different color pens. The one circled with blue needs tightened as well.
So, here is what to do: Loosen the two bolts (circled with blue and black). Once they are loose, tighten the one circled with red, which is the tensioner. Once the belt is tighter, then retighten the bolts with blue and black circles.
As far as something for the belt, they make a belt dressing. I personally don't like using it because it doesn't last and can make a mess of things.
Let me know if this is the procedure you used to tighten the belt. Also, if the front bolt isn't tight, it could allow the alternator to sit on a slight slant and cause noise.
Take care and let me know the results.
Joe
See pic below.
Image (Click to make bigger)
Friday, December 10th, 2021 AT 7:13 PM