BMW Expansion Tank Cap for 1/2/3/4/5/6/7/8 Series & more (2006–2025)

For BMW 1/2/3/4/5/6/7/8 Series & 1 Series M/M2 & X1/X3/X4/X5/X6/X7 & Z4 & i8 from 2006–2025, BMW supplies this Expansion Tank Cap as an Original BMW replacement component. It stores expanding coolant and provides the system’s fill and recovery point. The supported range includes 1 Series M, 128i, 135i, 135is, 228i, and 230i, plus additional listed variants. As an Original BMW component, it is produced within BMW’s own vehicle-specific design and testing program.

Technical Details

• Manufacturer part number: 17-11-7-639-020
• Manufacturer: BMW
• Component: Expansion Tank Cap
• Primary function: stores expanding coolant and provides the system’s fill and recovery point
• Vehicle applications: BMW 1/2/3/4/5/6/7/8 Series & 1 Series M/M2 & X1/X3/X4/X5/X6/X7 & Z4 & i8
• Production range: 2006–2025
• Listed models: 1 Series M, 128i, 135i, 135is, 228i, and 230i, plus additional listed variants

Fitment & Compatibility

Review the table below for year-by-year model coverage, submodels, and any listed equipment notes. Match the engine, hose or connection layout, cooling-system equipment, and production date. PMB Performance has more than 20 years of experience matching European vehicle parts; send us your VIN if you need help confirming fitment.