The hearts of your cooling system are the Audi water pumps. This is the device that makes it possible to generate high temperatures in your engine and then they carry it away so the components do not melt. Every Audi has a water pump and they are located on the front of the engine. The drive for them is the center pulley which is rotated by the actions of the serpentine belt. The inspection of the water pump on your Audi or any car is slightly difficult. This is because when the seal of the pump fails it drips water out of a little hole on the bottom of the pump near the end of the short shaft that sticks out of the water pump. In most instances this hole is obstructed from view because of the pulley on the end of the shaft. There are multiple reasons why the seals on your water pump fail but the most common is that the coolant you have in your Audi is old or water was placed in your cooling system instead of coolant. It is essential that all Audi water pumps have coolant running thru them. In the coolant there is a special additive that lubricates the seal and prevents it from prematurely failing. If this part is beginning to fail, a wet spot where you park your car that will be seen near the front of the engine. If a failing water pump is ignored for too long of a period it could cause not only the overheating of your vehicle, but the shaft from the pump to will no longer be secured in alignment and the serpentine belt could become loose. This will cause your engine to stop running where it happens and you will be calling a tow truck for a lift to the nearest garage.