Can't find a manual?
Go to dealer or call 800.for.merc and order the W163 Service DVD
http://www.startekinfo.com/StarTek/outside/8763/?requestedDocId=8763
Or, as an alternate, subscribe for a day at
http://www.startekinfo.com and download to your heart's content.
While you're at it, subscribe for free to the parts manual system, i.e. EPC.
Mercedes has you very well covered--why would you think differently?