One-time overheating issue

RLara485

I've owned my 2012 since late February, it was originally dealer inspected and zero issues since. This past week, after approx. 15 minutes of idling in a parking lot (typical) the car began to overheat a bit, it just moved up three notches from normal operating temp. Coolant was fine, I went in to work and drove home later no problem.

Took it to the dealership today. No leaks, fan is working, thermostat is working, they had it for about 8 hours and could not get it past normal temp. They flushed the coolant in the possibility of an air pocket, which was fine since I was going to do that this winter anyway but I don't know how an air bubble would form out of nowhere.

I do notice this car reaches operating temp. really fast compared to anything I've owned; as in, I close the garage door and am barely down the street and it's already at normal..... but I figured it was just a Z thing and it never overheated so I never gave it attention.

Anyone have any insight on this? I've been driving it hard and can't get it to overheat again. I'm in central TX and that day I believe it was about 107 with the heat index, but that's every day here... of course the oil temp is in the 220-240 range constantly but I never had a problem with the water temp.