Don't be so quick to criticize. It is a WATER cooled alternator. What do you think it will do if it overheats? If the coolant is low certain circuits could be starved. In the e46 the cabin heater will stop working BEFORE the low coolant light even comes in.

I'm not theorizing. I'm telling you what I have observed on my newly acquired X5 over the last few months.

It may be something else in this car. But it takes 5 min to open the overflow tank and top it off and try it again.

Thaniel