Genuine OEM Audi Engine Coolant Thermostat, part number 06J121113A. This vital component precisely controls the flow of coolant within the engine, ensuring it quickly reaches and maintains its ideal operating temperature. It functions by opening and closing to direct coolant either through the radiator or bypass it, as needed. Constructed with a precisely calibrated wax element and durable sealing components, it offers reliable and consistent temperature management. Selecting a genuine OEM thermostat guarantees the correct temperature calibration and long-term durability, essential for engine health, fuel efficiency, and consistent cabin heating.