In this guide, you will find instructions on how to manually rotate (turn over) the crankshaft on Mercedes-Benz engines.
What you will need
To manually crank a Mercedes-Benz engine you will need the following tools:
- Park your Mercedes-Benz and set the parking brakes.
- Allow the engine to cool down.
- Pull the hood release under the hood.
- Remove the front part of the engine cover by lifting it up.
- Locate the crankshaft pulley at the front of the engine.
- Place the 27mm socket on the bolt at the center of the crankshaft.
- Rotate the ratchet clockwise. Do not rotate the engine counter-clockwise.
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 note that as the various cylinders reach the Top Dead Center (TDC), turning the crankshaft will get harder than easier once past the TDC.
If you are having a hard time turning over the engine, remove the drive / serpentine belt, and try again. If it is still difficult to manually crank your Mercedes-Benz engine, remove the spark plugs.
If your crankshaft won't turn, then you most 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 a number of maintenance procedures including for 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.