Overheating 2011 Dodge Journey

2011 Dodge Journey is overheating. New Thermostat, system was purged. Had a diagnostic done and bubbles were purged from system. there are no leaks from head gasket or water pump. Vehicle still overheats and coolant bubbles in radiator.

Of you have coolant bubbles in the rad and no head gasket leak, where are the bubbles coming from?

Are these bubbles coming before the temperature is above normal in the radiator? Has your coolant been tested for the presence of exhaust gas?