The effective viscosity temperature dependence of the lubricant is taken into consideration within the thermodynamic model of boundary friction. Transitions between the friction kinetic modes are described as the second-order phase transitions. For the system kinetic investigation the mechanical analogue of the simple tribological system has been considered. The time dependences of block coordinate, velocity, friction force and shear stress have been build. Therefore, the stick-slip motion has been described for a wide range of the system parameters. A comparison of simulation results with experimental data in sequence increasing shear rate has been made