Technical Service Bulletin B170420 — 2019 BMW M850I

COOLANT LEVEL CHECK AND TOP-OFF AT SECOND OIL SERVICE: A new, additional coolant level check task is now linked to the second engine oil service (Service Counter 2 only). The scope of maintenance work will display in ISPA Next that applies to the high-temperature circuit. This new coolant check only pertains to the above listed models with gasoline engines. During the normal operation of the vehicle, there is a certain amount of coolant absorption by the various components/gaskets/seals contained within the coolant systems. Over time, the coolant absorption can cause the coolant level to fall below the maximum fill level in the reservoir. In some cases, the level may even fall low enough to cause the high-temperature circuit low coolant level warning light to illuminate, along with displaying the corresponding Check Control message.