Hydraulic Oils

High Viscosity Index Hydraulic Oil

For machines that start below freezing and run hot the same day, or work across a wide seasonal range on one fill. Holds viscosity across temperature better than a standard grade.

Features

  • Keeps viscosity closer to the pump's design window at both ends of the working range, which reduces cold-start cavitation and hot-running wear.
  • Allows one fill across a season where a standard oil would need two, which simplifies a depot's holding.
  • Shear stability is the property to ask about: a high index achieved with a shear-unstable improver loses viscosity in service.
  • Usually worth the cost on machines with variable piston pumps and on anything left outside overnight in winter.
  • The fluid's viscosity at the highest measured system temperature is the figure to check, not the grade at 40 degrees C.

Specifications

Figure Typical range Unit Why it matters
Viscosity grade at 40 degrees C 46 mm2/s the nominal grade, comparable to a standard oil
Viscosity index 150 - 200 the property being bought
Viscosity at 100 degrees C 8.5 mm2/s what the pump actually sees when the machine is hot
Shear stability viscosity retained after shear testing an unstable oil loses its advantage within weeks
Pour point -36 degrees C the cold-start limit for outdoor plant