Q: Temperature reading hot cold air blowing out of vents both side set at 90 degrees. Northstar will I blow a head gasget??

Hello. It is likely if the vehicle is getting progressively hotter, that it is going to overheat sooner or later. The head gasket is one of the several components that can be a factor, but you will want to test a few other possibilities first. If there are no leaks, and the coolant is full, you will want to make sure your thermostat is working. If it does not open when the temperature reaches its limit, then the coolant will not circulate in the engine. The water pump is responsible for circulating the coolant, and naturally would cause overheating if it fails. If the head gasket was blown you would likely be consuming coolant and notice the levels getting lower. Be careful, as overheating the engine will ruin it every time. Do some further testing on the vehicle and go from there.