AGING OF MOTOR OIL
Qualitative and quantitative changes of motor oil parameters take place, when the engine is operating: viscosity and acidity rises, deterioration of additives and accumulation of wear and tear products occur. It is ascertained that the utmost condition of the lubricating oil is reached by 500 hours of vehicles ’ operoperation, and a minimum concentration of barium in the motor oil must not be lower than 0,15 %.