There often exists gas hole and leakage defects in lost foam casting aluminum alloy straight six-cylinder engine housing. Origination of the defects is very complex. Filling and solidification process of the engine housing were simulated to predict potential defect position. The results reveal that existing gating system can result in severe temperature gradient in the engine housing after filling. Meanwhile

different ingates exhibit distinctly different in fluid volume

where the maximum different value reaches up to 20%

which is responsible for the formation of gas hole in engine housing as a result of not realizing self-feeding.