Timing Chain -Seized?
 

I was replacing the water pump housing on my 300D and turned the crank pulley counter clock wise. Now my engine will not turn over. Some say it is seized, some say the timing chain is bunched up. Need advice? Here is a video to my problem
https://www.youtube.com/watch?v=gvHupp3TuPo&list=UU7ti52TKOduxGE8yjWSifSg

I live in Michigan by Ann Arbor if anyone wants to mentor me or suggest a shop.

The timing chain is only meant to turn clockwise, turning the engine over backwards means slack probably built up in the chain (the chain tensioners only work one way) and you may have pistons hitting valves...

STOP RIGHT NOW!!!!!!!!!!!

Do not use the starter you WILL break something.... IT is possible that the timing chain has skipped a tooth. This can happen if the engine is rotated the wrong way.

First thing I would do though is remove the waterpump belt and see if you can bar the engine over by hand. It is possible that the new pump is the wrong size or something and is binding is a way that would prevent it from turning, thus keeping the engine from turning.

Next would be to pull the valve cover and check the timing..... and we'll go from there

I don't think it is likely at all that the chain has skipped a tooth but turning the crank pulley anti-clockwise is big no no. The chain is probably snagged. This most likely means at least one chain guide is toast.

If you can't turn the crank CLOCKWISE by hand =>

Remove the valve cover and see if you can see an obvious problem - you probably won't...

...remove the chain tensioner on the right hand side of the engine (so that's left hand side standing in front of the car looking at the engine scratching your nuts thinking why oh why?) and see if that gives you enough slack in the system to turn the crank CLOCKWISE. Use a deep 27mm socket and a long bar to get it to go.

Lots of other videos started to play after I saw the one where you see an engine and hear a click (the cat star wars one is probably the best - tree felling and bird feeding not my thing) and I got distracted - have you got a turbo or non turbo OM617?

I did not look at the Video.
Is this a Turbo Diesel? If it is not a Turbo Diesel the Large Timing Cain Rail and Timing Chain Tensioner are more easily depressed compared to the Turbo Diesel. Making turning the Engine backwards more problematic.

Hmmn, do turbo and NA engines have different timing chain tensioner setups??

Yes. the non-turbos have a Spring and Piston Tensioner and at higher Engine Speeds the Oil Pressure behind the Piston does a lot of the Work pushing the Piston out to tension the Chain Rail.

The Turbo 617 Engines have a ratcheting device that when the Piston moves out a circular Spring snaps into a Groove and prevents the Piston from being pushed Back. Oil Pressure also pushes it forward.

So while both Engines should not be turned Backwards the Turbo Engine is less likely to have a problem from that because the ratcheting device makes it difficult to push the Piston backwards.

In the pic is blow up of the part of the Tensioner Piston that has the retcheting device on the Turbo 617 Engines.

Had a friend come over and took the valve cover off. The top end appears OK, he thinks the crank is seized. Think I am going to sell the car because rebuilding or repairing the engine is a costly adventure.

Have you try turning the engine "clockwise" and "slowly" manually?
If its a piston hitting the valves you will fill it.

I just tried to change a chain on a different car last weekend, it was bad, really really bad... It kept jumping and I lost the timing... Thne the pistons were hitting the valves.
I was lucky with trial and error I put the old chain back where it was ...

Just to say you will feel it if its a valve.
Good advice to take the pump out too, might not be the right one? just to clear all possibility.

Unless you are not owning up to something else that has happened I can't see how changing the water pump has seized the crank. You haven't touched the timing chain at all have you? The engine didn't seriously boil did it? (and even if it did I'd expect damage to be elsewhere first) You've just turned the crankshaft anti-clockwise...

Seized
 

The crank will not move at all, but some play in the chain. The piston is not hitting the valve because it was up

Crank
 

All I did was turn the crank, everything else was the waterpump and housing.

Well you're convincing me that the chain is just stuck.

I can't see any possible way that turning an engine manually could seize the crank. It has to be the chain.

I'm thinking the course of action would be to start pulling things apart. Take the water pump off and the chain tensioner. Then start taking out the chain guides starting with the long one on the top. At each phase, gently move the crank fore and aft to see if you can get it to release itself.

Assuming it frees up, then you'll need to ensure it hasn't jumped a tooth.

How many turns did you turn the crank pulley CCW and why did you have to do that in replacing a water pump? Are you currently able to turn the crank in either direction with a 27 mm deep socket on the crank pulley nut?