Genuine OEM Audi Engine Coolant Radiator, part number 1S0121253AN. This primary component of the engine cooling system is responsible for dissipating heat from the engine coolant to the ambient air, thereby maintaining optimal engine operating temperatures and preventing overheating. It is typically located at the front of the vehicle, behind the grille. Weighing 2.471 kg, this genuine OEM radiator ensures factory-specified core design, material quality, and connection points, providing efficient heat exchange, leak-free operation, and long-term reliability for the entire cooling system.