The clutch is that mechanical part located in an internal combustion engine vehicle which allows the torque transmission from the shaft to the wheels, permitting at the same time gear shifting and supporting engine revolutions while the car is idling. This component exploits friction as working principle, therefore heat generation is in its own nature. The comprehension of all the critical issues related to thermal emission, and also of the principal physical parameters driving the phenomena are a must in design phases. The subject of this paper is the elaboration of an accurate, but also easy to use and easily replicable, methodology to simulate thermal behavior of a clutch operating inside its usual environment. The present methodology allows to prevent corrective actions in the last phase of the projects, such as changes in gear ratios, that likely worsen CO2 emissions, permitting to achieve the wished thermal performance of the clutch avoiding late changes. Using computational fluid dynamics, coupled with thermal-FEM software, working limits can be foreseen, and strengths or design flaws can be highlighted. The approach for the problem is typically bottom-up: starting with the simulation of a reduced domain around the clutch and going towards the complete car thermal simulation. Here, the aim is to show the setup of a thermal simulation, considering boundary conditions, initial conditions and geometry details. Starting from a reduced computational domain, many more attempts can be run and a final model more easily found. Consequently, a sensitivity approach to several aspects will be adopted: heat generation location and temperature of different components can be considered to evaluate the impact on the clutch thermal behavior. The paper will show the correlation between experimental and virtual results for both complete and reduced models, to identify the best trade-off between computational efforts and accuracy.