Collect the useful evidence
Record the warning and any visible traces after the vehicle has cooled. Note recent cooling-system work. Ask the workshop to inspect the cylinder-head-to-expansion-tank line and test for other leaks rather than repeatedly topping up without finding the cause.
Sources 1
Check the VIN before assuming coverage
BMW’s 2025 document describes a component-specific warranty extension, not a recall. The model-year range alone does not establish eligibility. Have the VIN and repair diagnosis checked; unrelated cooling-system repairs are not automatically included.
Sources 1
Sources / references 1
- BMW SIB 01 05 25 — G30 coolant expansion-tank breathing line ↗Reviewed Sep 27, 2026
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