An airflow directional control system in an agricultural harvester having a grain tank or other structure, an internal combustion engine and a cooling system cooler box disposed between the grain tank or other structure and the internal combustion engine includes a cooler box cover over the cooler box between the grain tank or other structure and the internal combustion engine, at least one air director between the cooling box and the internal combustion engine and a panel adjustment system controlling tilt of side panels of the harvester.