belt tensioner supposed to vibrate? what are those marks?

[cutlass1991]

I looked that the tensioner while the engine was running and it seems to vibrate a lot. Is that normal?

 

Also, what are those markings used for and is mine aligned correctly?

 

[manitcor]

those are wear markings I belive, as the sprin weakens the tnesion will rotate toward/away from one line and closer to the other. If you say its vibrating alot then its due for replacment. $50 from most auto parts stores.

[94cutlatized]

thanks manticor, always wondering what that was. Dont mean to change the subject, Dan, but is that ground effects on the cutlass? will they fit 94 and up?

[THe_DeTAiL3R]

If it moves at all from side to side then replace it. It happened to out 3.1 Lumina APV and the serpentine belt fell off. Luckly that didn't hurt anything, but after trying to put the belt back on the tensioner busted (spring popped out).