How to manually crank engine

[sbetts]

Hello,

I have a 1974 450SEL than has not been driven in over 20 years. I want to see if the engine will move, but have never cranked an engine with a wrench. How do I? It looks like there is a plastic white cover over the crankshaft end, but before I pry it away I figured I'd check with you all to make sure that is the correct place to do this, and to hear other suggestions. What size socket would I need?

[daantjie]

For starters you need to remove all the plugs so you're not fighting compression.  You need a long wrench as well.  Turn clockwise facing the engine.  There is a large nut on the crank pulley for which you need correct socket and extensions as the nut sits pretty deep.

[Pete49]

I would add some light weight oil via the plug holes and let it sit for a while before trying to crank it. You would need to do a fluids before starting anyhow.

[Pete49]

oops double post

[Max-NL]

You will need a 27mm socket. I would recommend a deep socket and a short extension.