The Audi radiator and coolant hoses used on your automobile are made specifically for that application. Different year Audis along with different models are for the most part not interchangeable. This is not done on purpose, but because of the way the engineers have to place all of the necessary components under the hood of your vehicle. The radiator and cooling hoses for your car are made of copper, brass, aluminum and reinforced polymers respectively. The design and placement of them on you Audi are done to shorten the distance between this cooling system and the hot engine it is made to keep it in a specific operational range. This range is also maintained with the use of a thermostat that is located at the exit point of the coolant on the engine. The reason coolant and not water is used in the radiator and coolant hoses of your Audi are to help widen the range in which the cooling effects of this liquid can operate in. It boils higher and freezer at a lower temperatures than water. To be fully effective the presence of some water is required. It is the way the coolant is designed to work. The coolant has a secondary function in your engine other than just maintaining the right temperature. It is also the lubricant for the water pump, radiator and coolant hoses in the cooling system. This lengthens the lifespan of the Audi radiator and coolant hoses and associated cooling parts so replacing them is minimized. Since the radiator and coolant hoses are critical components on your vehicle, regular inspections are recommended. On the radiator a deposit on the fins or around the hose connections should be looked for. The hoses should be inspected for cracks and wear just like the engines belt is. They are made out of similar material and show the same types of wear patterns.