The spreading behavior of automobile oil in soils is a critical factor influencing hydrocarbon contamination, soil degradation, and remediation strategies. This study examined the effects of oil concentration (1500–3000 mg/kg) and time (6–12 hr) on oil spreading rate using a central composite design (CCD) within response surface methodology (RSM). Thirteen experimental runs were conducted, and spreading rates were measured in centimeters. Statistical analysis revealed that the quadratic model provided the best fit for the experimental data (R² = 0.9714; Adj. R² = 0.9510; Pred. R² = 0.8290). Both oil concentration and time had significant effects on spreading rate, with strong interaction terms and quadratic effects further influencing the results. Theoretical physics concepts, including Darcy’s law, capillary flow theory, adsorption dynamics, and Density Functional Theory (DFT) approximations, were integrated to interpret the underlying mechanisms of oil migration in porous soil media. The findings indicate that oil spreading in soils is a nonlinear process governed by the interplay between concentration-dependent capillarity and adsorption phenomena. This combined experimental–theoretical framework provides valuable insights into oil transport in soils and serves as a basis for developing effective environmental risk assessment and remediation strategies.