Recent automobile engines are equipped with many devices that are driven by oil pressure. Generally, engine oil is used for oil pressure, and in addition to its conventional functions of lubrication and cooling, etc., it also plays an important role in accurately driving such devices. One of the factors that can interfere with the characteristics of engine oil is air contamination. Excessive air contamination can cause issues with driving devices. Although there are various factors that contribute to air contamination, this paper focuses on, and attempts to help predict, the air generated by engine oil falling and colliding with the surface of the oil in the oil pan as it returns from the top to the bottom of the engine. Using the particle method as the prediction method, the coupled Moving Particle Simulation (MPS) and Discrete Element Method (DEM) calculations were used to represent the generation of air. Basic tests were conducted to computationally reproduce the behavior of each of the factors necessary for help predicting air generation in actual engines, namely, the flow of engine oil on the wall, the air floating in the engine oil, the defoaming at the oil surface, and the air generated due to the collision of the engine oil with the oil surface. Then, using the parameters identified in the basic tests, an attempt was made to help predict air generation using an actual engine model. When the shape of the baffle plate that receives the oil flow from the top of the engine was changed and the difference in air ratio at the oil inlet was verified, a good correlation was obtained between the change in air ratio measured on the actual engine and the change in air ratio predicted by the computational model.