BMW 12317508054 Exchange Alternator, Water-Cooled

The water-cooled alternator is an enclosed unit mounted on the engine-block, within the circuit of the water jacket and is, therefore, an engine-cooled unit. For these reasons, it is a 'brushless' sealed unit and cannot be serviced: the temperatures need to be kept constant to prolong the life of the unit. It also has the welcome side-effect of removing the alternator cooling fan, which results in even less noise. Also incorporated in this alternator is the load start reduction which reduces the time to start an engine particularly in cold climate because during starting the current load is limited to only 20 amps to minimize the alternator braking torque on the engine and as the starter engages full output is progressively developed.