The Temperature gauge you are referring to is the "Oil Temperature Gauge" to the left of the tachometer...Is there a water temperature gauge in a different "menu" somewhere ??
In the case of my Toyota the water temp gauge would not have helped provide any warning. In that case:
Inappropriate coolant chemistry caused the cast iron cylinder block head gasket surface to corrode.
The shortest distance between the coolant channel and something else was to one of the cylinders.
Once this path is established pressurized coolant sprays into the cylinder until there is not enough coolant for the water pump to circulate.
Then the engine overheats very quickly.
The corrosion is slow, taking years to become a problem. The rest of the problem advances very quickly (a few minutes or less). Once the coolant level drops the water temperature sensor is no longer immersed and provides no indication that the engine is overheating. The first warning is lack of power as the engine starts to seize from the heat.
Apparently Toyota brand coolant had the right chemistry to avoid this problem, but Toyota did not specify that only their coolant was to be used in their engines. So anyone who changes the coolant for their favorite brand eventually encountered this problem. I think more modern non-Toyota coolants have the necessary additives.
At least AR chose an all aluminum design, which is less prone to this corrosion problem than aluminum heads on a cast iron cylinder block.
A new engine that is spraying oil into the coolant system more likely has a manufacturing flaw than any kind of corrosion or design flaw. I presume that AR will be doing a postmortem analysis in order to be certain.
