Shielding vehicle underbody or engine room components from exhaust heat is becoming a difficult task with increasing packaging constraints, which lead to the proximity of components with high temperatures of the exhaust systems. Heat insulators are provided to protect various components from exhaust system parts. Generally the requirement of heat insulators are fixed on the basis of benchmarked temperatures measured on vehicles with similar layout, during the initial phase of vehicle design.Also various CFD techniques are available to predict the surface temperatures on components in order to determine the necessity of a heat insulator. The aforementioned techniques use radiation and convection heat transfer effects on a complete vehicle model and the overall process generally takes considerable time to provide the results.This paper deals with a theoretical approach to predict the temperatures on nearby components due to exhaust system heat. The mathematical model focuses on radiation effect as it is the primary mode of heat transfer from exhaust system to surrounding objects. Validation of the model has been done by comparing its results with the values obtained from actual testing on the vehicle. The predicted temperature values were found to correlate with the temperature data obtained from testing.Using this approach, temperature prediction can be done in a short span of time compared to detail CFD simulation. The results can be utilized for taking decisions in advance for heat insulator requirements and any component layout changes, during the early stages of vehicle design.