That's exactly the purpose of that plug. It is a provision for a mechanical
tach. There is an o-ring in there that will leak after a while. Leaks from
this plug are commonplace as these cars are getting up in years.
Mathieu
If I recall correctly, older OM61x engines (or maybe it was OM621
engines) had a takeoff to attach a mechanical tach to the engine. It
looked like it would be where a distributor would be on a gasoline
engine. Engine oil could migrate around the cover if it were loose MAYBE!?
Marshall
--
Marshall Booth (who doesn't respond to unsigned questions)
"der Dieseling Doktor" [EMAIL PROTECTED]
'87 300TD 181Kmi,'87 190D 2.5 199Kmi, '84 190D 2.2 227Kmi, '85 190D 2.0
159Kmi, '87 190D 2.5 turbo 234kmi
Diesel Technical Advisor MBCA, member GWSection
http://www.dhc.net/~pmhack/mercedes/mbooth1.htm
