Our 2015 Chevy Trax AWD LTZ (50K miles) had both engine light and overheat light flashing and buzzer going off. Mechanic replaced coolant tank and cap and added coolant (code said vacuum issue)...still overheating...then replaced thermostat. The car still reaches overheat after running a while. Head gaskets and seals were tested and test ok. Now performing a flow test on the water pump. If not that then perhaps a clogged radiator$$$$$. Has anyone faced this issue and if so what was your remedy or what do you suggest the problem may be???