Your car should be chassis 116. I have a 123.
If you look under the hood, the engine shutoff is the one marked "STOP". One the 123 and 126, it is a brown line. I do not know what color it is on the 116.
I do work on my car. I took auto mechanics in High School just so I could do my own repairs. I do like turning wrenchs, but I do not do it for a living. I graduated from HS a year after my car was made. Then I stuffed 4 years into 4 1/2 for college.
It is the first MB diesel I have owned. They are really quite easy to work on. Some things can be a pain, but my 82 model 123 is MUCH easier to work on than my '73 Pontiac or '77 Chevy PU ever was.
Networking is a great thing, and it is hard to find a good mechanic that has experince with these cars. You are better of learning these cars, because only you will make sure the job is done correctly. I can help out also.