This forum is great. Just the info I was searching for:
I drove the Mirage on the freeway yesterday again for the second time since I got it in November and noticed via the ScanGauge that the coolant temp crept up to 216 F when under its highest load (slight incline). Conditions: the ambient temp was just above freezing, and the car has a partial grille block, cruising speed around 100 km/h / 60 mph on mostly flat terrain.radiator fan comes on at 220 F and turns back off around 206 F.
I got concerned that the coolant temp was "high" and the radiator fan hadn't kicked on, so I cranked up/modulated the cabin heater to drop the coolant temp to around 200.
In my Metro & Firefly, the radiator fan comes on at 204F. Thus my concern.
Obviously Mitsu is comfortable with a higher operating temperature. Higher temp = higher fuel efficiency.