Theoretical investigations are carried out for a plain journal bearing considering the influence of thermal effects on non-Newtonian lubrication. With reasonable assumptions, the steady state and dynamic characteristics are presented using a thermohydrodynamic analysis of a bearing lubricated by a nonlinear, i.e., cubic, fluid model. Experiments are conducted on a rig to study the steady state and dynamic performance of a full journal bearing with different types of non-Newtonian lubricants. Experiments include the measurements of eccentricity ratio, critical speed, and stability limit. The theoretical investigation reveals that the interaction of the non-Newtonian effect and the thermohydrodynamic effect is strong for friction, and the interaction effect is negligible in the case of eccentricity ratio, attitude angle, and lubricant flow rate. Further, for relatively high values of non-Newtonian parameter, αn, the effect due to the non-Newtonian parameter is not negligible. © 1992 Taylor & Francis Group, LLC.