What percentage of water in the oil is critical?

Each OELCHECK-lab report lists how much water is in the oil. This value is given as a percentage.

There is usually no more than 0.1% water in the hydraulic oil in our Liebherr excavators: Nevertheless, we want to know:

What percentage is critical?
When is it necessary to change the oil?

OELCHECK answers:

The percentage of water in the hydraulic oil should basically not exceed 0.12%. The range of 0.10 to 0.12 % is already critical. Here, at least oil-care measures should be taken. Above a concentration of 0.12%, however, it is essential to change the oil because of too much water in the oil.

By the way - this is how water can penetrate into the oil:

  • As condensate, because the machine "breathes". At a temperature difference of 50 °C, 100 liters of oil expand by 3.5 liters. As it cools, moist air is drawn into the circuit and then the water it contains is separated as condensate.
  • During steam cleaning
  • In the event of a defective cooler
  • As rainwater that has been on the lid of the oil drum for a long time.

In the analysis, OELCHECK can even demonstrate whether it is normal tap water or condensate.