bio and gnolo,

If your question is whether or not the engine is siezed, then turning it by hand will answer the question. If you want to do a compression check, then you have to turn it over at a speed more representative of the engine running. The best alternative is the starter for compression checks.

I understood the original question to be to determine if the engine or the transmission was siezed, or both. Once that is known, addressing the starter questions will be more definitive. Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)