What are the factors that cause changes in viscosity of the lube oil?
Changes in viscosity, should always be considered in relation to other parameters like Index of Contamination (IC), Water content, TAN (Total Acid Number) and Closed Flash Point. a) High insoluble level will make the oil viscosity rise. b) Water content could either make the oil viscosity rise or fall. c) Increasing TAN usually indicates-oil oxidation which would make the oil viscosity increase. d) Distillate Fuel contamination would make the oil viscosity decrease while Residual Fuel contamination would either make the oil viscosity increase or decrease depending on the viscosity of the fuel. Regular oil analysis is an important tool in monitoring oil viscosity enabling the operator to keep the situation under control.
