Currently, full vehicle computational fluid dynamics (CFD) simulations are used to predict rear fascia temperatures. As these simulations are expensive and time consuming, only what is intended to be a worst case scenario analysis is completed. Certain variables can be overlooked and the case selected may not be the worst case scenario. The objective of this thesis is to create a surrogate model that can rapidly predict maximum fascia temperature for a variety of vehicle operating conditions and exhaust positions, while exploring the physical mechanisms responsible for the heat transfer between the exhaust gas, exhaust components, and rear fascia. Using full vehicle CFD simulations, an investigation of the maximum fascia temperature as a function of vehicle operating conditions and exhaust positioning is completed by identifying non-dimensional parameters governing maximum fascia temperature, consisting of both geometric and non-geometric parameters based on vehicle speed and exhaust inlet velocity (Reynolds number), their ratio (velocity ratio), and exhaust temperature (exhaust temperature ratio).