BMW 3 Series 2012–2015 — technical service bulletin
Bulletin SIB-12-33-14 · NHTSA communication 10058476 · issued Mar 1, 2015
Technical service bulletin
communication type
Engine and Engine Cooling
component
2012–2015
model years
6
vehicle entries
Official summary
Bmw: due to transmission oil heat exchanger's faulty thermostat or engine faulty characteristic map thermostat, engine coolant fails to reach operating temperature, with low heat output and service engine soon light comes on. No model years listed. *pe
What a TSB means. Technical service bulletins are repair guidance manufacturers send to dealers — they are not recalls, and repairs are not automatically free (warranty extensions are an exception worth checking). The full document is available via NHTSA’s vehicle lookup.