The test I ran was at idle speed in my driveway. I don't remember having been caught in heavy traffic at 105deg (these conditions are fairly rare in our neck of the woods).
But I've seen around 95-100deg. in traffic where the inside temp. was cold enough for the fan to run at medium speed.
The W124 system is better than my wife's 2003 Accord. It cools more rapidly than the Honda does and cools much better.
JackD