wait and see what the new thermostat does. there was a similar post a few days ago on an e320. i have driven a clk 55 and the temps hover in the 85-90 range in traditional MB fashion yours is borderline on the high side. also, check the concentration of your coolant, 40% to 50% works best....
1993 300e-2.8 - gone now <sigh>
"Do not adjust your mind, it's reality that's malfunctioning"