Oil on 2011 W204 Alternator

[PaulJ6152]

I had to remove the under tray of my 2011 2143cc C class, to drain the coolant. While under the car I noticed the alternator is coated in what looks like oil. It’s not dripping just coated. No oil above it or in front or behind. I’ve looked to see where it might have come from but nothing obvious.
Does anybody have any thoughts where it maybe coming from?
Paul

 

[amazighman]

Turbo inlet oil seal perhaps

I had to remove the under tray of my 2011 2143cc C class, to drain the coolant. While under the car I noticed the alternator is coated in what looks like oil. It’s not dripping just coated. No oil above it or in front or behind. I’ve looked to see where it might have come from but nothing obvious.
Does anybody have any thoughts where it maybe coming from?
Paul