Among the main tasks of every vehicle fleet operator is to ensure trouble-free service, is the priority being to secure the trouble-free running of vehicle engines in all operating conditions. Last but not least, efficiency is also required. Due to the greater oil content in bus vehicles than automobiles, there is an effort made to change the oil after the longest time of operation. This paper will compare the results of determining the content of impurities in the engine oil with the REO 31 device according to the methodology used in the laboratory of tribotechnical diagnostics, Jan Perner Transport Faculty, University of Pardubice and with the TCM device according to the methodology used in transport companies.
