Hydraulic Fluids

Multi-viscosity or multi-grade hydraulic fluids are widely used in mobile equipment operating in all-season use because the ambient temperature varies outside the recommended range of a single grade conventional fluid. Some examples are tracked excavators, wheel loaders, municipal waste trucks, snow plows, utility company lift trucks, and hydraulic cranes.

Multi-grade hydraulic fluids contain a viscosity modifier (VM) and a pour point depressant (PPD) in addition to the hydraulic performance package. The VM raises the fluid’s viscosity index (VI) and helps the fluid viscosity remain more constant over a wide temperature range while the PPD controls wax crystallization ensuring the lubricant continues to flow at cold temperatures. High performance multi-grade fluids offer better wear protection, greater operating efficiency and smoother hydraulic system response, year-around, under the toughest conditions.

Performance factors are important when choosing a VM for multi-grade hydraulic fluid.

  • Shear stability or resistance to viscosity loss in service 
  • Viscosity Index increase 
  • Low temperature fluidity 
  • Fluid filterability 
  • Water separation ability 
  • Other performance common to high quality hydraulic fluids

Contact your Lubrizol representative to learn more about differentiating your hydraulic fluid brands with market leading performance with the help of Lubrizol viscosity modifiers.