why didn't you shut it off? what's the point of idling in a lineup? got money to burn?
how hot it can get depends on your particular setup, fan position in relation to the rad [high/low or far away, shroud or not], the fan is the only thing that keeps air flow across the rad when you're stopped - 210 isn't going to hurt it, but it should be able to keep the temp pretty close to the thermostat rating unless the fan is poorly positioned and it's quite hot out .... and you're sitting in a line breathing someone elses hot exhaust
Bill
