BMW 7-Series Coolant Expansion Tank Replacement DIY (2016-2022 BMW G11/G12 740i, 745e, 740e xDrive)

BMW is notorious for its cooling system woes, and this latest generation of 7-series models isn't immune. The expansion tank is a critical part of the cooling system, acting as a reservoir that ensures the system stays properly pressurized. Unfortunately, the constant heat cycling will wear down the plastic tank, leading to cracks

Replacing the expansion tank is slightly involved, although it only requires a few hand tools. You will need to open the cooling system, which requires a refill and a purge. Space can also be tight, even in the 7-Series engine bay.

In this video, FCP Euro's Professional DIYer Mike Hidalgo replaces the coolant expansion tank in a G11 BMW 740i.