A method of controlling a vehicle engine compartment cooling system by cooperatively controlling both a variable grille opening and engine cooling fan based on a number of vehicle inputs. Maximum component cooling demand, vehicle speed, and ambient temperature are inputs to lookup tables that issue grille opening demand and engine cooling fan demand. Additionally, vehicle overall power consumption is considered in the development of the lookup tables. A vehicle computing unit selects grille opening settings and cooling fan speeds that correspond to demands from lookup tables. A control signal is sent to an adjustable grille actuator and to a fan motor. Further, vehicle deceleration events are used to trigger a full open grille opening setting, allowing increased cooling at little or no loss to vehicle efficiency. A benefit of the disclosed method is optimal settings to minimize the grille opening for aerodynamic performance while providing required engine component cooling.