BMW recommends replacement of the engine coolant expansion tank cap every 30,000 miles, as preventive maintenance.
This part is listed by BMW as BMW part number 17138665638 (17-13-8-665-638) and is described as Genuine BMW Cap for Coolant Expansion Tank for G42 2-series, G20 3-series, G22/G23/G26 4-series, and G29 Z4 models.
For full BMW fitment information or for assistance from one of our BMW experts, we recommend calling us at 877-639-9648.
BMW Fitments:
2 Series
G42 / G43 (2022+) > 230i
G42 / G43 (2022+) > 230i xDrive
G42 / G43 (2022+) > M240i
G42 / G43 (2022+) > M240i xDrive
3 Series
G20 (2019+) > 330e
G20 (2019+) > 330e xDrive
G20 (2019+) > 330i B46D (2019-2024)
G20 (2019+) > 330i B46P (2025+)
G20 (2019+) > 330i xDrive B46D (2019-2024)
G20 (2019+) > 330i xDrive B46P (2025+)
G20 (2019+) > M340i B58D (2019-2024)
G20 (2019+) > M340i B58N (2025+)
G20 (2019+) > M340i xDrive B58D (2019-2024)
G20 (2019+) > M340i xDrive B58N (2025+)
4 Series
G22 / G23 (2021+) > 430i B46D (2021-2024)
G22 / G23 (2021+) > 430i B46P (2025+)
G22 / G23 (2021+) > 430i xDrive B46D (2021-2024)
G22 / G23 (2021+) > 430i xDrive B46P (2025+)
G22 / G23 (2021+) > M440i B58D (2021-2024)
G22 / G23 (2021+) > M440i B58N (2025+)
G22 / G23 (2021+) > M440i xDrive B58D (2021-2024)
G22 / G23 (2021+) > M440i xDrive B58N (2025+)
4 Series
G26 (2022+) > 430i Gran Coupe B46D (2022-2024)
G26 (2022+) > 430i Gran Coupe B46P (2025+)
G26 (2022+) > 430i xDrive Gran Coupe B46D (2022-2024)
G26 (2022+) > 430i xDrive Gran Coupe B46P (2025+)
G26 (2022+) > M440i xDrive Gran Coupe B58D (2022-2024)
G26 (2022+) > M440i xDrive Gran Coupe B58N (2025+)
5 Series
G60 (2024+) > 530i B48P (2024+)
G60 (2024+) > 530i xDrive B48P (2024)
G60 (2024+) > 540i xDrive B58N (2024+)
G60 (2024+) > 550e xDrive B58X (2024+)
7 Series
G70 (2023+) > 740i
G70 (2023+) > 740i xDrive
G70 (2023+) > 750e xDrive
Z Series
G29 Z4 (2019-2025) > Z4 M40i
G29 Z4 (2019-2025) > Z4 sDrive30i
