Installing the coolant expansion tank of the high-temperature coolant circuit

WARNING: This page is about a different car, the 2025 BMW M4, 2024 BMW M4, 2023 BMW M4, 2022 BMW M4, and 2021 BMW M4. However, it is still accessible from the selected car via links, so may be relevant.

WARNING: Hot surfaces .
Risk of burning!

Perform all work only on components that have cooled down.

NOTE: TECHNICAL INFORMATION
Immobilization period-long fill of coolant!
Do not reuse used coolant.
When replacing and removing components which rely on the corrosion protection effect of the coolant, it is essential to change the coolant. The cooling system must therefore be emptied and refilled.
In the case of other removal work involving the draining of part quantities of coolant, the coolant level must be topped up with new coolant.

NOTE: TECHNICAL INFORMATION
Make sure that the connections are locked correctly. The locks must engage audibly.

Check rubber mount (1) for correct fit.

Courtesy of BMW OF NORTH AMERICA, INC.

Position the coolant expansion tank (1).
Connect and lock coolant line (2).
The coolant line (2) must audibly engage.

Courtesy of BMW OF NORTH AMERICA, INC.
Guide and install coolant expansion tank (1) into rubber mount (2) in the arrow direction.

Courtesy of BMW OF NORTH AMERICA, INC.
Tighten the screws (1).

TIGHTENING TORQUE SPECIFICATIONS

Coolant expansion tank to strut brace ring
Hexagon screw M6x16	Tightening torque	8 Nm

Courtesy of BMW OF NORTH AMERICA, INC.

Secure the clamp (1).

Courtesy of BMW OF NORTH AMERICA, INC.
Connect and lock coolant line (1).

Courtesy of BMW OF NORTH AMERICA, INC.
Fasten connector (2) on the holder (3).
Connect connectors (1) and lock.

Courtesy of BMW OF NORTH AMERICA, INC.
Connect and lock coolant ventilation line (3).
Coolant ventilation line (3) must engage audibly.
Secure cable (2).
Connect connectors (1) and lock.
The connector (1) must engage audibly.

Courtesy of BMW OF NORTH AMERICA, INC.

Follow-up work

Refer to INSTALLING THE STRUT BRACE .
Refer to CONNECTING THE COOLANT LINE TO THE RADIATOR .
Refer to INSTALLING THE BOTTOM FRONT RIGHT SIDE COVER .
Refer to INSTALLING THE STIFFENING PLATE .
Refer to INSTALLING THE LEFT AND RIGHT FRONT UNDERSHIELD .
Refer to INSTALLING FRONT UNDERBODY PROTECTION .
Refer to INSTALLING THE FRONT SPOILER .
Refer to INSTALLING RIGHT INTAKE SILENCER HOUSING .
Refer to FILLING AND VENTING THE HIGH-TEMPERATURE COOLANT CIRCUIT .