Stainless steels are now widely used for automotive exhaust systems, driven by the need to increase the durability of exhaust systems, which are subjected to severe conditions and include components of high technology such as manifold, catalytic converter and particle filter. This causes a direct consequence of the effort to decrease automotive pollutant emissions due to the new environmental regulations throughout the world. During the last few years, the increasing use of stainless steel fabricated exhaust systems has led us to develop new grades, to study new production technologies of forming and welding. Modern exhaust systems must withstand severe cyclic mechanical and thermal loads in an engine cycle. Up to now, highly loaded parts of exhaust systems are predominantly designed experimentally by means of lengthy and expensive component tests. A further shortening of development time without quality loss is possible only by increasing application of computer simulation. For an engine development program, the engine exhaust manifold is a complex system subjected to thermo mechanical loads.The aim of a series of coupled computational fluid dynamics-finite element, CFD-FE, simulations performed here, was to investigate the thermo-mechanical behavior of a stainless steel engine exhaust manifold which is in early stage of design. It is going to be designed for the national diesel engine of IPCO, EF7, instead of the existing cast iron one. For this purpose, both fluid flow and solid walls are considered simultaneously.Furthermore the heat transfer coefficients for the CFD calculation will be evaluated.We assume that there is steady state, incompressible and turbulent flow with k-? turbulence model. The overall flow situation in the exhaust manifold is very good. There are no parts in the geometry with high pressure losses or high mach numbers. With the help of a code developed in MATLAB, the HTC’s will be mapped on the FE mesh for the thermo mechanical analysis. The thermo mechanical analysis includes a thermal and a stress calculation. Since the failure of the exhaust manifold is mainly due to the geometric constraints of the less expanded inlet flange and cylinder head, the analysis is based on exhaust system model with three-dimensional temperature distribution and temperature dependent material properties. Large compressive plastic deformations are observed for the elevated temperature of thermal shock cycles. The first calculation loop showed a high level of plastic strain, primary at the joints between runners and the flange. In the second loop the bore diameters of flange were upsized, so that the flange can slide free at the gasket plane.As result of this change the plastic strain is decreased strongly. Gapping at the gasket between exhaust and cylinder head for the case of thermal expansion was determinate. Keywords: Exhaust Manifold, CFD Coupling, Thermal Stress