This guide provides instructions on manually rotating (turning over) the crankshaft on Mercedes-Benz engines.

What you will need

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To manually crank a Mercedes-Benz engine, you will need the following tools:

  • 27mm socket
  • Ratchet Wrench


turn-over-crank-mercedes engine
  1. Park your Mercedes-Benz and set the parking brakes.
  2. Allow the engine to cool down.
  3. Pull the hood release under the hood.
  4. Remove the front part of the engine cover by lifting it.
  5. Locate the crankshaft pulley at the front of the engine.
  6. Place the 27mm socket on the bolt at the center of the crankshaft.
  7. Rotate the ratchet clockwise.

Do not rotate the engine counterclockwise.

You will need to apply a considerable amount of force. V8 and V6 engines are harder to turn over than V6 and 4-cylinder engines.

Also, as the various cylinders reach the Top Dead Center (TDC), turning the crankshaft will get harder than easier once past the TDC.

If you have difficulty turning over the engine, remove the drive / serpentine belt, and try again. Remove the spark plugs if it is still difficult to crank your Mercedes-Benz engine manually.

If your crankshaft doesn’t turn, you will likely have a mechanical problem, such as a broken timing chain, bent valves, bad bearings, etc.

Mercedes-Benz Engine Won’t Turn Over.

Typical problems that can prevent a car from turning over include.

  • Seized starter
  • Damaged crankshaft bearings
  • Engine hydro locked.
  • Engine sized
  • Timing chain problem
  • Bent valves”

This is often necessary if your Mercedes does not start and you want to verify that the engine is not seized or locked up.

This procedure is also required for several maintenance procedures, including changing the timing chain, checking for timing chain wear, time injection pump, camshaft replacement, etc. If your engine will not turn over, in most cases, it is due to mechanical problems.

We hope you find the “Manually Turn Mercedes-Benz Engine Crankshaft” guide helpful. Check these troubleshooting and repair guides for more help on your Mercedes-Benz.

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One Comment

  1. Anonymous says:

    I have a 420 engine that needs a camshaft, currently they are : 08 and 09 camshafts. What cams
    would fit and increase H.P. and performance ?