Is your belt tension correct? That would be the first question to answer when determining if the tensioner is bad. Removing the alternator the way you did does not really say anything bad about the tensioner.

While a TIGHT belt might ruin the bearings in an alternator... No, belt tension would not make the alternator go bad in four months.

Did you really drive 12,000 miles in four months?

You can remove the fan from the clutch with an ordinary metric hex key.

The shroud is easy to remove.

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2012 E350
2006 Callaway SC560