This bulletin applies to 2020 BMW M5 Sedan, M8 Convertible, M8 Grand Coupe, X5 M and X6 M vehicles, equipped with the S63 engine.
Coolant may leak from under the car, and a low coolant warning might be displayed. The cause: chemical/thermal reaction with the tank’s plastic material and the coolant.
Drain all coolant from the engine, replace the expansion tank and fill/bleed with new coolant. Note that there a specific instructions for expansion tank replacement based on the model. The instructions must be followed to ensure that the coolant does not leak onto the fuel injectors during the replacement of the tank.
The new expansion tanks are available as follows:
M5 and M8 vehicles............... 17 13 7 889 450
X5 and X6 vehicles................. 17 13 8 689 765
