On certain 330i xDrive models, the bearings on the engine counterbalance shafts may not be installed correctly. This could cause the counterbalance shafts to loosen, and result in severe engine damage or an engine failure. An engine failure would cause a sudden loss of power with an inability to restart.
A sudden loss of engine power could increase the risk of a crash.
BMW will notify owners by mail and instruct them to take their vehicle to a dealer to replace the engine.