The paper presents an analytical mathematical model of a car radiator. which takes into account various heat transfer coefficients (HTCs) on each row of pipes. The air-side HTCs in a specific row of pipes in the first and second passes were calculated using equations for the Nusselt number. which were determined by CFD simulation by the ANSYS program (Version 19. https://www.sahmbuffy.com/product-category/existalite-xcr-combo-units/