MITZONE Aluminum Coolant Expansion Tank — G30 G32 G12 G14 G15 G16

Built to directly replace OEM part numbers 17139846642 and 17139884859, this tank fits a broad range of 2016–2020 BMW applications including the 530e, 530i, 530i xDrive, 540i, 540i xDrive, 640i xDrive Gran Turismo, 740e xDrive, 740i, and 740i xDrive. Aluminum's inherent thermal stability means the reservoir maintains its shape and seal integrity even under the sustained heat and vibration loads your turbocharged inline-six or plug-in hybrid powertrain generates — conditions that steadily degrade the OEM plastic over tens of thousands of miles.

Installation is completely straightforward. MITZONE engineered this tank to match the factory mounting points, connection ports, and sensor bungs precisely, so there's no drilling, adapting, or fabricating required. Swap out the old unit, reconnect your coolant lines and sensor harness, refill with BMW-spec coolant, and you're done. It's the kind of upgrade that pays for itself the moment you avoid a roadside coolant failure or a costly cooling system flush from a cracked tank contaminating the system.

For BMW owners who prefer to stay ahead of known failure points rather than react to them, the MITZONE aluminum expansion tank is a sensible, permanent fix. Whether you're maintaining a daily driver or prepping a weekend cruiser, upgrading from plastic to aluminum here is one of the most practical reliability investments you can make on these G-series platforms.