The present work aims to investigate the different casting defects that arose during the gravity die casting process of an IC engine block made of AA 7075 alloy and also highlights the feasible solutions to eradicate those defects. The minimization of the casting defects is a very crucial task in an IC engine block. Experimental studies which are generally performed to reduce the casting defects are proven to be strenuous, costly, and time-consuming. To counter this, a thermal simulation model is proposed in the present study to identify the effect of the pouring temperature, mould temperature, and the number of chillers on the various casting defects such as cold shuts, air entrapment, mould erosion, and microporosity. A detailed parametric study is conducted on the proposed model to evaluate the outcomes of important process variables on the resulting casting defects. The simulation results predict, at pouring temperature of 963 K, mould temperature of 293.15 K and with the use of 2 chillers defect-free IC engine blocks can be casted. The optimum result obtained by the proposed model is validated by conducting a confirmative test predicting an average error of 6.98%. The proposed model is effective enough in getting rid of the numerous casting defects which cannot be identified using the traditional methods; thus increasing productivity. This can be used as an economical time-saving substitute to the experimental methods during casting of various engine parts.