For the poster's sake, are you talking about the top grooved idler or the main 90mm smooth idler?

Also, I noticed our main 90mm smooth idler is the newer updated one from Mercedes already, with the green bearing. Mine spins smooth and quiet after 34K miles.

As for my upper grooved small idler, when I bought the car used it didnt spin well so I replaced it. 8K miles later the new one doesn't spin well anymore either.... Hmmmm.