The article entitled Monitoring of engine oil degradation and possibilities of life prediction in combustion engine deals with chronological monitoring of engine oil on the monitored object -a passenger car with a petrol engine. The research concerns the basic physico-chemical parameters of motor oil, where it discusses the operational factors that contribute to its degradation. The theoretical part of the thesis deals with the analysis of the current state of the problem in the chemical composition of engine oils, analysis of the current state of contact indicators of oil quality in lubrication systems of internal combustion engines and analysis of contactless systems "live" evaluating engine oil quality during vehicle operation. The research part of the work includes the collection of operational data, laboratory analysis of oil samples and statistical processing of the results of tribodiagnostic monitoring. This article discusses the 1st phase of extensive long-term research in the field of tribology and operation of the Mitsubishi Lancer 1.5 Inform motor vehicle.

Today, modern tribodiagnostics offers sophisticated analyzes of motor oils with fast and accurate results. However,Today, modern tribodiagnostics offers sophisticated analyzes of motor oils with fast and accurate results. However,finding the causes of some undesirable processes of engine oil degradation often requires long-term monitoring of the operatingfacility. In this case, it was a problem of diesel engine oil in the Citroёn Jumpy 2.0 HDi service minibus, which has been in useby the Department of Mechanical Engineering (Armed Forces Academy of General M. R. Štefanik, Demänová) for more than13 years. The fuel system (conditioners of injectors) on this vehicle has also been monitored for a long time in the period 2019-2021, an article about it was also published in the journal Science & Military (No. 2 / Vol. 14/2019). The cadets of theDeptartment of mechanical engineering Armed Forces Academy of General M. R. Štefanik, were also involved in the diagnosticprocess. In parallel with the fuel system, the quality of the engine oil was regularly monitored in the time interval 20.1.2020 -22.4.2021 at a start of 2185 km from the last oil change. During this monitoring, a very rapid degradation of engine oil wasfound in some parameters, which is atypical during normal vehicle operation. This article discusses the measured results andpossible causes of this adverse event.