The normal operating range is about 80-105C. At 100C the mechanical fan clutch tightens, but it does not provide enough air flow at idle, so the temperature may continue to climb. At about 105C the auxillary electric fan(s) engage, and the temperature should drop quite fast to 100C where they disengage.

Continued low speed traffic will repeat this cycle until you get up to a steady speed above about 40 MPH when the temperature should drop to somewhere between 80 and 90 unless it is over 100F ambient.

Duke