Hydraulic Fluid vs Motor Oil - In the current world, the largest class of hydraulic fluid consists of refined hydrocarbon base oils or petroleum oils with various additives by supplementing them to the base oils to create inherent properties in the fluid. To be specific, a standard hydraulic oil consists of 99% base stock like mineral oil and 1% is additives such as antiwear.
On the other hand, engine oil has a much more complex composition compared to the simple composition of hydraulic oil. They consist of 78% of base oil, 3% detergents (cleans the engine), 10% additives which are to improve the viscosity (to improve flow), 5% of dispersant ( for the suspension of dirt particles), 1% of wear protection, 0.001% of antifoam and other components with a percentage of three.
