April 1, 2022 Service bulletin

The quick disconnect coupling on the cylinder head coolant vent line could break at the cylinder head

BMW technical service bulletin B170121 for 2012-2016 BMW 328I, 2017-2020 BMW 330I and 2012-2017 BMW 335I and others.

Bulletin number: B170121
Component: Engine and engine cooling
Summary: The quick disconnect coupling on the cylinder head coolant vent line could break at the cylinder head. This would lead to loss of coolant from the engine.

Owners of these vehicles have filed 759 complaints in the engine category.

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