4E0121212B Genuine OEM Audi Auxiliary Radiator, part number 4E01212B. This part functions to supplement the main cooling system, ensuring optimal engine temperature under various conditions. It is typically located in the front of the vehicle, often behind the main radiator. Constructed from durable materials to withstand engine bay temperatures and pressures, ensuring reliable performance. Genuine OEM radiators are manufactured to precise specifications for exact fit and optimal heat dissipation.