BMW Expansion Tank Cap for 5/6/7/8 Series & more (2004–2025)

BMW designed this Original BMW Expansion Tank Cap for the engine cooling system on BMW 5/6/7/8 Series & M2/M3/M4/M5/M6/M8 & X5/X6/X7 & XM from 2004–2025. It stores expanding coolant and provides the system’s fill and recovery point. The supported range includes 525i, 525xi, 528i, 528xi, 530i, and 530xi, plus additional listed variants. This genuine BMW-branded component carries BMW’s U.S. two-year, unlimited-mileage limited parts warranty.

Technical Details

• Manufacturer: BMW
• Component: Expansion Tank Cap
• Manufacturer part number: 17-11-7-639-021
• Production range: 2004–2025
• Vehicle applications: BMW 5/6/7/8 Series & M2/M3/M4/M5/M6/M8 & X5/X6/X7 & XM
• Primary function: stores expanding coolant and provides the system’s fill and recovery point
• Listed models: 525i, 525xi, 528i, 528xi, 530i, and 530xi, plus additional listed variants

Fitment & Compatibility

The table below lists the supported years and models; compare it with the vehicle before ordering. Match the engine, hose or connection layout, cooling-system equipment, and production date. Need a second fitment check? Send PMB Performance the VIN. Our team has more than 20 years of experience identifying European vehicle applications.