What are the reasons of oil ageing?

The nature and speed of oil ageing depend on the engine boost, quantity of fuel entering the oil, quality of fuel used in the engine, operating conditions, worn-out state of engine parts and units and the vehicle, etc. Oil ageing is accompanied by changes in its physical and chemical indicators. When exposed to water, acids, high temperature and load, additives added to the oil also actuate. This causes gradual loss of oil efficiency and necessitates its replacement with fresh one.