It's important for your Mercedes' engine to be kept cool. The engine is something that will generate a high amount of heat as you run it, which is why having a consistent flow of coolant to it is crucial. Your water pump is a part of the cooling system in your vehicle that helps to maintain the flow of coolant. When your water pump is working properly, your engine is able to maintain the proper operating temperature. There are some signs to look out for, however, that might indicate wear and tear on the water pump. If you notice there is coolant leaking from the front of your vehicle, this might indicate worn gaskets or seals that are attached to the part. You also might start to notice that the water pump pulley is loose or making whining noises. It's important to invest in an OEM replacement water pump for your car if it starts to wear out.