I began to have a relatively loud vibration coming from the engine compartment, which I narrowed down to the serpentine belt and pulleys. I proceeded to remove the serpentine belt and noticed that it was old and had several very stiff spots it in - almost assuredly the original belt. I proceeded to jiggle the other pulleys and idler and did not notice anything feeling loose or worn out. However, now I have installed the new serpentine belt and the vibrations have not gone away, although the vibration does seem be be less. I also noticed that the belt does not vibrate all the time - likely coinciding with the AC compressor engagement. The car now has 123kMi. My question is - when replacing the serpentine belt on these cars, should I have just automatically also replaced the idler pulley, shock absorber, and/or spring tensioner?

I must say, it's a bit frustrating to go through the work involved in changing this belt and have the belt continue to vibrate - even to the smallest degree. Any assistance would be appreciated.

Thanks,