Genuine OEM Audi Coolant Thermostat, part number 06B121111K. This essential component is responsible for regulating the engine's coolant temperature, ensuring the engine operates within its optimal thermal range. It manages the flow of coolant between the engine and the radiator. Constructed from durable plastic, this thermostat weighs approximately 0.51 kg and measures 0.16 meters in length. Installing a genuine OEM thermostat guarantees accurate temperature sensing, reliable valve operation, and proper sealing, which are vital for preventing engine overheating or undercooling and maintaining fuel efficiency.