When idling for a long time, and at least with the A/C on, I get the following behavior:
* The engine temperature will rise up to about 105 degrees, at which point the fan will go on, and the temperature will finally decrease.
* The temperature will decrease down to 95 degrees, at which point the fan will stop, and the cycle will start again.

This is surprising because the idle temperature on my M103 is pretty constant.

The other surprise is that since the fan seems then to be electrically rather than mechanically driven on the M104, it nevertheless doesn't stay on after switching off the engine, as is the case on other cars, and as I understood is one of the benefits of electric fans?

Interested in other experiences!

__________________
1991 W126 300SE (M103)
1995 W124 E320 Wagon (M104)