Check the coolant yourself. 30 miles is too long. Did you get any heat?

 

I did not check the coolant. It was just in for service (7500) and I would assume they checked it. BUT I will look at that tomorrow

 

Also the thermostat can fail and be stuck open. If so, then you'll have a cool engine and suffer excess gas usage (the engine will run rich to compensate for the cold, but the open thermostat prevents the engine from reaching operating warmth).

 

I hope the thermostat did not fail already. I have just over 10,000 miles on it.

 

If your thermostat failed and was stuck in the open position your engine would not have reached operating temperature with 5 degree outside temps.
We have a 2017 Optima LX 2.4L and a 2017 Sorento LX 2.4L and both of them seem to take a long time to reach operating temp when it is cold outside. BUT, after a few miles (at 35 MPH) the heater is putting out hot air.

I wouldn't worry about the temp because if the engine was running too cold for too long the ECM would set a code for this.

 

i just checked the coolant level. It is right between the F and L marks. I was getting warm air before it reached operating temp, but was having a hard time keeping the windshield thawed out. I assume the air coming out of the vents was not as warm as it is at operating temp. It seems like 30 miles at highway speed is a long way.

 

On my 2016 sx temp guage reads right in the middle.

 

My wife checked her 2017 Forte today to compare. It was warmer today at low 30's but her was at normal operating temp in 7 minutes

 

Is it 5 celsius or F%&#$%? Mine is 2014, but this morning it was 9F. By the time I headed out, it was in the teens, but I only drove for 2-3 miles before the heat started to warm up and he car temps went to normal.

 

Also consider getting a plug-in engine heater. But usually those are for bigger block engines, V6 or whatnot, because the tiny inline 4 of the optima usually warms up pretty quick. But, if you live in very cold conditions, the engine block heater might do the trick to get your engine warmed up in advance, assuming you put in on a timer to start warming the engine block before you leave.