Heat transfer plays an important role in the conceptual and the detailed design of cooling systems in internal combustion (IC) engines and has considerable influences over its operational performance. The demand for higher possible heat transfer rates has led to use a controlled transition from a single-phase convection to a sub-cooled boiling flow in hot regions, through the cylinder head. In order to achieve controlled boiling over a wide range of operating conditions, detailed flow and heat transfer analysis are essential. The computational fluid dynamic (CFD) simulation, incorporating the boiling model, is an effective approach for the thermal analysis of IC engines. In this paper, the water jacket of the national turbo-charged engine was simulated with the AVL-FIRE software to consider effects of boiling phenomena in the water jacket. For the validation of calculated results was performed through a test validation in a horizontal heated duct with two models, Chen and BDL models. It showed that the Chen boiling model was in better satisfactory with experimental data than the BDL model under the same conditions and could be used for calculating the boiling heat transfer in cooling passages of the engine. Contours of the pressure, the velocity, the heat transfer coefficient were demonstrated with and without consideration of boiling. Results showed that when boiling occurs, the heat transfer coefficient was significantly enhanced.