A three dimensional mathematical model has been developed to predict erosion in the engine internal surfaces. The model simulates the case of an engine operating in a dusty environment. The developed model relies on a modified version of KIVA-II code. Expressions for valves motion, instantaneous wall temperature and mutual interaction between the particles and the engine gas flow have been considered in this model. Erosion resulting from impinging particles on the engine internal surfaces has been predicted using the cutting and deformation model. Two approaches for the particles rebound behavior including both the deterministic and the stochastic approaches have been investigated. Also the effect of the presence of an oil film on the cylinder wall during the suction and compression strokes has been evaluated. This enabled the prediction of the engine oil contamination with particles. A parametric study for the effect of number of parameters which are related to the engine operating conditions as well as the characteristics of the particulated flow has been executed. It has been found that, the presence of the particles has a minor effect on the flow pattern inside the engine up to 1000 mg/m3. Parts which are subjected to erosion are mainly the inlet valve top face, regions in the cylinder head surrounding the intake and the exhaust valves and to a lower extent the piston face and the cylinder wall. Erosion increases with increasing the engine speed, particles loading ratio and the engine temperature, while it decreases as the particles size increases. The rate of oil deterioration increases with increasing the engine speed, loading ratio and particles size. The use of stochastic approach for the particles rebound behavior led to more spread erosion with less intensity compared with the deterministic approach.