Genuine OEM Audi Coolant Regulator Housing, part number 03F121111A. This component is designed to house the thermostat and precisely control the flow of coolant within the engine's cooling system, thereby regulating the engine's operating temperature. Weighing approximately 0.43 kg, it is a crucial part for maintaining engine thermal efficiency. Choosing a genuine OEM coolant regulator housing ensures exact fitment, proper sealing, and reliable temperature management, which are essential for preventing engine damage and ensuring optimal performance.