With ever-rising concerns about internal combustion engine emissions, a good prediction of the after-treatment inlet temperature in fast one-dimensional engine simulation codes become a must. Different simple models have been developed during the last years trying to better compute the turbocharger heat transfer phenomena. Although these models produce good results when computing the turbine outlet temperature, they focus on the axial heat transfer paths and lack the capability of producing detailed results about the internal thermal behaviour of the turbocharger. In this work, a new heat transfer model for automotive turbochargers is presented. This model discretises the turbocharger in both the radial and axial directions, and computes the heat transfer and temperature at different parts of the machine. Aiming for a low computational cost, it was designed to be compatible with fast one-dimensional engine simulations as a drop-in replacement of previous models. It might be used to compute the oil temperature inside the turbocharger bearings and lubrication channels during hot-stop events, thus allowing for the prediction of coke formation.