Description:

Xspeedonline Radiator Expansion Tank Cap, Coolant Reservoir Cap Cover 17117639020, 17117521071 for BMW 340i 2016-2017, 340i xDrive 2016-2017, 428i 2014-2016, 428i Gran Coupe 2015-2016 - 1.4bar. Replaces Part Numbers: 17117639020, 17117521071/ 17117639021, 17137516004. Critical Pressure Regulation Function: Serves as a pressure-regulating valve, maintaining proper cooling system pressure to prevent overheating and coolant issues.. Common Cooling Problem Solution: Addresses symptoms including coolant leaks, engine overheating, abnormal system pressure, and physical cap deterioration in vehicles.. Simple Direct Replacement: Engineered as a direct fit replacement requiring no modifications; simply remove the old cap and install the new unit to restore proper cooling system function..