After continuous hours of use, particles accumulate in the hydraulic oil. It is therefore important to regularly drain the entire hydraulic system to avoid any damage.

What’s the purpose of hydraulic oil?

Hydraulic and transmission oil does several things:

  • As it’s an incompressible fluid, the oil helps maintain pressure between the transmitter and receiver unit.
  • It reduces friction between the various parts, and protects them from scratching and premature wear.
  • The oil dissipates the heat evenly across the transmission components.  The hot oil is diverted back into the system, through a cooler, then to the hydraulic tank.
  • The additives and detergents in the oil help remove any foreign matter found in the hydraulic system. The oil will divert these impurities towards a filter which is located between the main hydraulic pump and the tank.
  • Hydraulic fluid protects the different components from corrosion. Hydraulic oil such as engine oil contains many additives to combat corrosion caused by water and atmospheric oxygen.

The different oil viscosity grades

The viscosity of the oil is its flow resistance and low temperature pumpability. Always refer to the instruction manual of your machine to choose an appropriate oil viscosity for the main hydraulic pump and the entire system, as well as for the machine’s application and the geographical area of ​​use.

Hydraulic oils for construction machines are generally grade 10W. HV 46 is another grade meant for industrial use of machine tools. 

A lower than recommended viscosity will result in poor lubrication.  On the other hand, if the viscosity is too high, the pump will struggle to circulate the oil, and will result in excessive consumption of the machine and poor heat dissipation of the hydraulic fluid, as well as poor lubrication.

CODIMATRA recommends a higher viscosity oil if the machine operates in an environment susceptible to strong temperature variations.

Why drain your hydraulic oil?

CODIMATRA advises that you drain regularly the entire hydraulic system. If you refuse to replace the oil regularly, all your machine’s hydraulic components are at risk of deterioration. Hydraulic oil undergoes strong thermal expansion and significant compression, causing it to gradually lose its properties. For improved cleanliness, we recommend that you replace the drain plug on the hydraulic tank when draining the used oil.  It is always best to refer to the machine’s instruction manual.

What to do with your used hydraulic oil?

Once the drainage is complete, the used oil must be disposed of correctly. That means taking it to either your local recycling centre, dealer or repairer or calling an accredited recycler.