Seems like you can know a lot about cars, but every time you get a new one, have a lot more to learn.
Use to be the radiator cap was the highest point of the cooling system, if that was full, entire cooling system was full. But had to remove the cap, when cold to check it.
Then they started to streamline the hoods, so that cap was never at the highest point. To get around this, had to jack up the front end of the vehicle so it was the highest point, ha, had to do this on my motorhome.
Gone is the radiator cap, now the recovery tank, but at least on the Cruze, back again to be the highest point, but you notice that the heater core hoses are much higher than the thermostat where the coolant temperature is located. In away, this is much easiest, no cap to remove, just look at it. But if it is low or empty, the heater core could be empty as well, and if it is, would be no coolant flow where it go back into the head.
But the thermostat is still lower, so you may not see at temperature rise while that head is overheating. Very quick way to check this inside of the vehicle, just turn the temperature control to max and switch on the blower, should get red hot heat. Granted, the Cruze should have put the temperature sensor back there, but somebody was not thinking.
When I first got on this board, read about many cooling system problems, so made a point to check it frequently, even for a short 40 mile trip, only takes a second. Ha, the Cruze could copy the Model A Ford with the fuel tank being the dash, just had a glass tube is see precisely the fuel level, none of that fuel sender crap. But this one would show that red coolant level.
Yes it is possible in this vehicle to show a normal operating temperature while your head is warping. If this happens to me, would be one very strong argument to get a new engine. But not at a dealer, but at the top.