Engine Radiator Cap Cover, Car Expansion Tank Replacement, Compatible with BMW 1 2 3 4 5 6 7 Series 2004 2019, OEM 17117639020 17117521071

【Precise Fit】Designed for BMW 1/2/3/4/5/6/7 Series models produced from 2004 to 2019. 【OE Part Numbers】Direct replacement for OE part numbers: 17117639020, 17117521071. Package includes: 1 radiator cap. 【Sealed Construction】Equipped with a high-density sealing gasket that forms a dual seal with the radiator neck after installation, effectively preventing coolant leakage and evaporation to avoid engine coolant loss. It also blocks external dust and contaminants from entering the cooling system, keeping the coolant clean. 【ABS Material】This radiator cap offers excellent high-temperature resistance, capable of withstanding prolonged heat in the engine bay without softening or deforming. The material also features strong aging and corrosion resistance, resisting erosion from oil and coolant to maintain structural stability over long-term use. 【Pressure-Regulating Design】Built to original pressure specifications, this radiator cap incorporates a precise pressure relief valve that automatically adjusts internal pressure in the cooling system. It effectively prevents damage from excessive pressure and avoids insufficient cooling due to low pressure, ensuring the engine operates at optimal temperature.