Proper sealing of an engine is very important parameter in an engine design. Even small amount of gas leakage from the engine can affect the overall performance of the engine during operation. There are two important factors in enhancing the efficiency of the sealing of the gasket are right tightening torque of bolts & gasket design. In this study, both the distribution of the contact pressure on the gasket, and the stresses of the cylinder head at different loading conditions, such as cold assembly, hot assembly, cold start, and hot firing, is simulated by commercial tool, based on the finite element method (FEM). The results shows that the efficiency of the sealing of the cylinder head gasket depends on the tightening torque of the hold-down bolts, without taking into consideration any thermal load resulting from the temperature distribution in the cylinder head. Study also shows that, the location of maximum contact pressure on the gasket is changed when the thermal loading is taken into account.