How to Remove the Water Pump on a Mercedes Benz 400E

1. Open the hood of the Mercedes 400E and allow the car to cool down if it is hot. Put the socket over the nuts holding the negative battery cable in place. Turn it to the left to loosen the cable nut and then slip if from the negative battery post. Do the same to remove the positive battery cable.
2. Place a drain pan beneath the radiator petcock, or drain plug. Turn the drain plug to the left with a socket wrench and allow the contents of the radiator to drain into the pan.
3. Open the radiator overflow tank by lifting the lid off with your hand. Also use a screwdriver to unscrew the hose clamp screw. Once loose, remove the radiator hose from the water pump.
4. Use a nut driver to remove the plastic nuts holding the fan shroud in place and then lift it out.
5. Unplug the fan's plastic wiring harness and then remove the fan bolt with the socket set.
6. Loosen the belt pulley tension bolt and slip the belt from the pulley and the water pump.
7. Use the socket set to remove the retaining bolts holding the water pump in place. Once the bolts are pulled out, gently lift the old water pump out of the engine compartment.