The oil sump sealing performance analysis has been carried out through the analysis of the joint formed by the sump flange, the engine block flange, the gasket, and the bolts. Oil sump flange bending plays a major role in affecting the gasket sealing performance, it is modeled using 3D shell element and reduced to a substructure stiffness matrix for the sealing surface. This reduced stiffness matrix along with the stiffness of the gasket and bolt are used in a 2D plate program to provide detailed gasket pressure profile on the sealing surface. The effect of sump wall height, corner bend, boundary conditions have been studied in detail to make sure that the lowest sealing pressure on the entire flange is at least equal to or larger than the predicted value. The effect of bolt spacing on the sealing pressure has also been studied, the results of which can be used as a guideline for bolt spacing specification in new engine development.