OK, then your engine may actually be overheating.
The gauge seems to be working correctly. The key to your problem is that the heater blows cold air sometimes. This is caused by an air pocket in the cooling system. The heater core cannot transfer heat into the car from coolant with air pockets.
You can easily check JN0-360 practice dump - pass4sure
with help of latest Avaya
latest resource University of Advancing Technology