This is my 7 year-old write up, with pics, for my M104 water pump at the time. Perhaps it an help:

http://www.peachparts.com/shopforum/tech-help/295118-m104-95e320-water-pump-dry-run.html

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2008 E350 4matic / Black/Anthracite

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Gone but not Forgotten:
2001 E430 4matic, 206,xxx miles, Black/Charcoal
1995 E320, 252,xxx miles, Black/Grey
1989 260E, 223,00 miles, Black/Black