That's why I'm confused. The shut off has always worked, but I have had problems with no vacuum at things like the heater core water-switch thing (I can't remember what it's called at the moment).


As for searching all I've been able to find is stuff for the 190E and then things like the 300. I use forums regularly so I know how to search. I get that there are people that don't, but I wouldn't post here if I could have found the information myself.


When I pick the car up later I'll see if I can do some testing myself, unfortunately work my work schedule it's likely it'll just be sitting for a while until I have time to fiddle with it.


Even if I do need to swap the pump I would like to have a diagram (why this isn't in the service manual boggles my mind) to assist in tracking down leaks that I'm sure are going to be present.

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2010 Mercedes E350 4Matic - 77k miles
1986.5 Nissan D21 V6 4x4 - 276k miles
1987 Mercedes 190D 2.5 Turbo - 3??k miles
1983 Mercedes 300SD turbo parts car
2017 Honda CBR500R - 15k miles
2016 Suzuki GSX S1000 - 9k miles