Hi. I have inherited a broken 87 300SDL and hope someone can help with my problem.
The car was originally thought to have spun off it's harmonic balancer while driving in town. On replacing the the keyway and balancer it was noticed that we could not turn the crank. We think the engine may have seized.There was no oil found in engine but we don't know if the mechanic before us drained it out.
Question 1. Should you be able to turn the crank from the bolt at the end of the crank or is the compression too great?
2. If it is seized, is a rebuilt or used engine the the only recourse?
3. Where would be the best place to find one.
4. What makes, models, and years would have the same engine.
Hope that's not too many questions, but I need to know so I can decide my next move.Thanks in advance :?

I turned my crank a few times...very slowly when adjusting the valves.

A big breaker bar...a few feet.

What Willy said - use a very long handle.

If the engine is dead, rebuilding would depend on your mechanical abilities. Paying a shop for a rebuild whould probably cost too much.

I'm not sure of a good source for used engines, but the same engine (designated OM603) is used in '87 300D's and TD's as well as '86 and '87 300SD's and SDL's. The 350SD used the OM603 motor, but in 3.5 liters. The early 3.5 liter engines had problems, but once they were sorted out they were wonderful.