To ensure the effective operation of engine cooling systems in agricultural tractors, several critical parameters must be considered, including grille opening area and location, grille resistance, front-end blockage, fan speed, and coolant flow rate. While grille design has been moderately explored for highway vehicles, research specific to grille configuration in agricultural tractors remains limited. This study investigates the influence of grille location, grille resistance - modeled using porous inertial and viscous resistance coefficients - front-end blockage, fan RPM, and coolant flow rate on radiator top tank temperature (TTT) using Computational Fluid Dynamics (CFD). The analysis is conducted in two phases: first, the effects of grille opening area and location, grille resistance, and front-end blockage are evaluated under fixed fan speed and coolant flow rate; second, an orthogonal array design of experiments is employed to rank the influence of grille opening area, fan RPM, and coolant flow rate. The CFD results exhibit strong correlation with experimental data, validating the simulation methodology. The insights derived from this study offer valuable guidance for exterior styling, vehicle integration, and thermal engineers working on off-highway vehicles, supporting the optimization of airflow and cooling pack design under constrained packaging and harsh operating conditions.