How to Remove the Water Pump on a Mercedes 300CE

1. Park your Mercedes on a flat area and let the engine cool for at least an hour before working on the vehicle. Open the hood and locate the serpentine belt routing diagram on the locking latch atop the radiator and fan. Use this diagram to find the serpentine belt tensioner pulley that needs to be released to remove the serpentine belt attached to the water pump.
2. Slot a socket plus the ratchet over the end of the bolt sticking out of the tensioner pulley. Rotate the bolt counterclockwise to loosen tension on the belt. Slide the belt off the tensioner pulley and allow it to return to its original position. Remove the belt from the water pump.
3. Place the drain pan under the plug on the bottom side of the radiator. Take the cap off the radiator as well as the overflow reservoir. Open the drain plug to drain the coolant out of the radiator. Replace the plug once it has finished draining.
4. Remove the hose from the top of the water pump. Loosen the hose clamp with a screwdriver. Detach the battery cables with a wrench. Remove the fan blade with a wrench or socket and detach the mounting brackets for the water pump in the same fashion. Remove the water pump from the engine block. Pry it loose with a screwdriver if it is stuck on.
5. Clean the engine block of debris from the old gasket. Mount the new gasket on the face of the new water pump. Set the pump against the engine block in the same place as the old one and mount it with the corresponding bolts. Reattach the fan blade and the radiator hose. Reconnect the battery cables. Slide the serpentine belt back over the water pump pulley and release the tension on the tensioner pulley to slide the belt back over the adjustor. Release the tension on the pulley and let the belt tighten. Remove your tools and close the hood of your 300CE.