Genuine OEM Volkswagen Engine Thermostat Housing, part number 03L121111AK. This critical component is responsible for housing the engine thermostat, which precisely controls the flow of coolant to maintain optimal engine operating temperatures. It mounts directly to the engine block as part of the cooling system. Weighing 0.299 kg and measuring 0.16 meters in length, this housing is engineered for durability. Using a genuine OEM thermostat housing ensures a leak-free seal, proper thermostat function, and reliable temperature regulation for engine longevity.