Does the starter turn at all, or is it inert?

If it turns and screeches, the overrunning clutch is shot had need to be replaced -- the is a one-way clutch that keeps the engine from driving the starter it you keep the key engaged after it starts. When it goes bad it screeches and won't let the starter turn the engine.

Certainly you need to splice the wire, but I though the starter wire was purple rather than green.

What you need to do next is to connect a test light or voltmeter to the starter solenoid on the start connection (the one that the battery cable ISN'T connected to) and attempt to start. If you have 12 V (0r the light lights up bright), the solenoid and/or starter are bad. If you get nothing, either the neutral safety switch, the wiring, or the key switch are bad. If you get low voltage or a dim glow, you ahve a bad or corroded connection somewhere.

This will at least tell you what you need. Don't depend on a mechanic unless he/she actually knows these cars.

You won't be able to rotate a hydrolocked engine with the flywheel or with a wrench on the crank pulley bolt.

If you get a stolid 'THUNK' but no engine rotation, and the dash lights (or headlights if on) go out, either the engine is locked up (you said it isn't) or the starter is. I jsut repalced the starter on the 300D last month for this very reason-- locked up tight.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!