Abstract The topic of the presented paper aims to demonstrate a new principle of hydrodynamic lubrication in mechanical, thermal and electro-magnetic fields. Up till now, when dealing with the hydrodynamic theory lubrication, many authors of scientific papers have assumed the constant oil dynamic viscosity value without variations caused by temperature crosswise the film thickness. Simultaneously, due to the numerous AFM measurements, it appears that oil temperature gradients and oil viscosity changes in the bearing gap height directions cannot be omitted. Therefore, in this paper, the problem of the viscosity changes across the lubricant thin layer was resolved as the main novelty in principles of mechanical thermal lubrication. The method of solving the mentioned problem was manifested by a general model of semi-analytical solutions of isothermal electro-magneto-elastohydro-dynamic and non-Newtonian, lubrication problem formulated for two deformable rotational surfaces in curvilinear, co-ordinates.