OK I'll bite... how many amps does it draw?
The inside fan can use up to 20 amps and so can the aux fan in front of the radiator. If you have an early car you should update the wiring and alternator to the 80 amp version used after 1990.
The problem we see with many early cars is that the 65amp alt (even the 70 amp ones with spade connections at the output) only produce 50-60% output at idle. The bigger alternators not only put out more but they put out 75% or more at idle.
Basically its all a matter of addition. 20a (inside fan) + 20a (outside fan) + 10a (headlights) + 15a (ignition/fuel pump)= 65a. The alternator is lucky to do that at 2000rpm. Its probably more like 35a at idle. It all adds up to big trouble.
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician