BMW X3 2018–2021 — technical service bulletin
Bulletin B640121 · NHTSA communication 10190864 · issued Mar 1, 2021
Technical service bulletin
communication type
Back Over Prevention
component
2018–2021
model years
7
vehicle entries
Official summary
WHISTLING NOISE COMING FROM FRESH AIR INLET (ENGINE COMPARTMENT): A whistling noise is present from the fresh air inlet area (engine compartment bulkhead area), in the right front area of the vehicle, at speeds above 40 mph.
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.