The belt is always the first thing I'd check. It could be worn or glazed or stretched so far that it doesn't get good tension on it. You can replace it in about 15 minutes without pulling the fan off or anything. You just need to make sure you either have the path diagram or draw one before you take the old belt off.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz