BMW Expansion Tank Cap for 2/3/4/5/7 Series & Z4 (2019–2025)

Replace the factory expansion tank cap on BMW 2/3/4/5/7 Series & Z4 from 2019–2025 with this Original BMW part. It stores expanding coolant and provides the system’s fill and recovery point. The supported range includes 230i, 330e, 330i, 430i, 530i, and 540i, plus additional listed variants. BMW states that Original BMW Parts are designed, tested, and manufactured by BMW.

Technical Details

• Component: Expansion Tank Cap
• Manufacturer part number: 17-13-8-665-638
• Primary function: stores expanding coolant and provides the system’s fill and recovery point
• Vehicle applications: BMW 2/3/4/5/7 Series & Z4
• Production range: 2019–2025
• Manufacturer: BMW
• Listed models: 230i, 330e, 330i, 430i, 530i, and 540i, plus additional listed variants
• Listed submodels: M40i, M40i First Edition, sDrive M40i, and sDrive30i

Fitment & Compatibility

Check the fitment table below against the vehicle’s model, production year, and submodel. Match the engine, hose or connection layout, cooling-system equipment, and production date. PMB Performance can review the VIN when model-year or equipment details are unclear, drawing on more than 20 years of European-parts experience.