I was recently facing similar problem. Engine was overheating in stop& drive traffic, on highway it was all good.
In stop&go traffic temperature reached 110 Celsius and then fan kicked in and temperature was dropping.
After flushing, thermostat and radiator cap I finally found the cause: it was fan resistor. It caused 1st speed of fan not to engage, and waited until temp is high and 2nd fan speed engaged.
After replacing temperature is stable. It seems that resistor controls the speed of the fan.
kejno got a reaction from 2late4u in Over Heating