The results of modeling and bench testing friction losses in the main engine kinematic nodes for different lubricating oil temperature values was presented in the article. The study was performed to evaluate the effect of lubricating oil temperature on the engine friction losses. In addition to friction losses in the crankshaft bearings and the piston rings in a cylinder-piston group the friction loss due to charge exchange in the cylinder, drive of timing system and the oil pump were measured. The obtained results show the course of the friction loss in the combustion engine. The research shows that the thermal state of the engine lubricating oil has effect on the amount of friction losses. Formulated conclusions allow to assess the impact of the oil temperature on the friction losses in the main friction nodes in combustion engine.