I am running thermal stress analysis on an engine block. The goal is to ensure that the block won't fail during use. The bore of the block is subjected to a temperature of 480K. There are water channels inside the block for cooling the block, there are subjected to coefficient convection with convection 3000 W/m^2K and bulk ambient temperature of 360 K. The sides of the block is subjected to convection from air with convection coefficient 5 W/m^2K and bulk ambient temperature of 298 K.The block is fixed at the bolt holes. However the stresses that are being obtained are significantly above yield stress. I want to know how to remedy this. This is because the physical block operates under the given conditions and it has not failed.
Please find attached the results.