The dynamic viscosity thus obtained was transformed into the kinematic viscosity of the oil by dividing it by density. To determine the dynamic viscosity of hydraulic oil at 40◦C and 100◦C, we used a water bath. Thus, we determined the dynamic viscosity of the hydraulic oil with the Schott Ubbelohde viscometer at the temperatures of 40 and 100◦C. Methods: To determine the kinematic viscosity of the hydraulic oil, we used a calculation formula that transforms the dynamic viscosity into kinetic viscosity knowing the density of the fluid. The study also intends to determine the viscosity-temperature coefficient for the hydraulic oil. These methods are: the viscosity index determined by a mathematical relationship, using a calculation program and the graphic method. Objectives: To determine the viscosity index of hydraulic oil by three methods.
