See also:

Remove attached parts following use
Remove auxiliary mirrors, roof or rear luggage racks which are no longer required following use. Attached parts on the vehicle impair the aerodynamics and increase the fuel consumption. ...

Maintenance
The battery is maintenance-free, i.e., the electrolyte will last for the life of the battery. Your service center will be glad to advise you on questions regarding the battery. ...

BMW 320d: powerful torque, outstanding smoothness and further improved fuel efficiency
The new-generation BMW 3-Series Sedan features the BMW TwinPower Turbo four-cylinder diesel engine of its predecessor, which has been honed for even greater fuel economy and lower emissions with n ...