Again, your car is ifferent. The SOV (in this instance) is an electrohydralic valve on the side of the IP. See #11 http://www.detali.ru/cat/oem_mb2.asp?TP=1&F=210025&M=606%2E962&GA=722%2E608&CT=M&cat=19T&SID=07&SGR=045&SGN=01

BTW, there is no such thing as a '93 E300D.

Does yours say "300D / 2.5 Turbo" or "300SD / Turbodiesel" on the trunk? That will clarify if you own a W124 with the 602.962 or a W140 with the 603.971 engine. Put it in your "signature".

Guessing its a 2.5 turbo as the 300SD's wern't common. Regardless of which, your bolt is just a bolt. http://www.detali.ru/cat/oem_mb2.asp?TP=1&F=124128&M=602%2E962&GA=722%2E418&CT=M&cat=502&SID=07&SGR=120&SGN=04

If it was a 95 "E300 / Diesel" the bolt would be a manual kill switch push button valve.