With the increasing stringency of emission regulations, auto makers are now improving vehicle fuel efficiency via all kinds of technologies, such as hybrid systems, turbocharged or supercharged engines, engine auto start/stop, active grille shutters, etc. By implementing a variety of technologies, the engine cooling module’s working environment and work load has changed. This paper will mainly focus on the impact to the thermal durability of the engine cooling module’s main radiator from active grille shutter and electric thermostat implementation. A 2017MY hybrid vehicle using the above technology is evaluated by a wind tunnel test at a variety of ambient temperatures and driving conditions. First, such technologies’ control logic is studied by the wind tunnel test, so that the evaluation condition for evaluating the radiator’s thermal stress can be properly chosen to represent the actual field usage. Then, a single variable method is used to understand the difference in thermal damage mechanism between traditional and new technology conditions, as well as quantify the impact on radiator thermal damage for active grille shutters and electrical thermostat individually. Lastly, such understanding of the mechanism and quantified damage difference can be utilized to evaluate if the radiator thermal durability is adequate for the field when there are vehicle model changes.