Piston slap is one of the sources producing engine block surface vibration and mechanical noise. To analyze piston slap-induced vibration, a realistic but simple model is proposed and verified experimentally. A piston is modeled by 3 degree of freedom system and an impact point between piston skirt and cylinder wall by 2 degree of freedom system. Numerical simulation estimates impact forces of piston in cylinder, and the engine block surface vibration response is predicted by the convolution of the impact forces with measured impulse responses. Experimental verification on the predicted response had been also performed by using a commercial 4-cylinder diesel engine. The predicted and experimental vibration responses confirm that the suggested model is practically useful.