Genuine OEM Audi Coolant Regulator Housing, part number 03C121111H. This essential component is part of the engine cooling system, specifically designed to house the thermostat. Its primary function is to regulate the flow of engine coolant, ensuring the engine operates within its optimal temperature range. Weighing 0.66 kg and measuring 0.2 m in length, this housing is engineered for precise fitment and reliable performance. Opting for a genuine OEM coolant regulator housing ensures proper sealing, material integrity, and accurate temperature regulation, which are crucial for preventing engine overheating and maintaining long-term engine health.