In order to determine the seizure limit of the main bearings of passenger vehicles under actual operating conditions, evaluations were conducted in environments containing noise factors (Various factors which designer cannot adjust and which make function vary were defined as noise factors in this paper.) [1,2] It was shown that noise factors have an effect on seizure limit performance in relation to performance under ideal test conditions (test conditions in which no noise is present). In relation to oil properties, the results showed that a reduction in viscosity as a result of dilution affected seizure limit performance. In relation to the shape of the sliding sections of the test shaft, seizure limit performance declined in a shaft in which the central section was swollen (“convex shaft” below). With regard to partial contact between the shaft and the bearings, it was shown that as the angle of partial contact increases, the seizure limit declines, and that the magnitude of this effect differs depending on the material used in the bearings.