An apparatus for controlling airflow to and a temperature of an engine may employ a radiator with liquid coolant, a first roller positioned parallel to an inlet tank and a second roller positioned parallel to an outlet tank, and a single film shutter that winds upon each roller. Thin strip leaders define gaps for airflow to reach the radiator. A method of controlling an open position of the film shutter may entail calculating a first film shutter open position based upon an engine coolant temperature, calculating a second film shutter open position based upon an air conditioning output pressure, comparing the first film shutter open position to the second film shutter open position, determining the larger open position, and moving the film shutter to the larger open position to expose a greater radiator surface area than the smaller open position.