The book examines the increase in the efficiency of the use of hydraulic systems of road and construction machines (RCM) in the low temperatures of the Russian North (Yakutia). The analysis of the natural and climatic conditions of Yakutia, the methods and means of maintenance and repair of the hydraulic systems of the RCM at low temperatures is carried out, the processes in the hydraulic systems of the RCM during technological operations are considered, the methods of mathematical modeling of the hydrodynamic systems of the RCM, the experimental study of the hydraulic systems of the RCM, an example of determination is given. The influence of low temperatures on the thermal regime of the hydraulic units of the DZ-98 motor grader, recommendations are given.