Transfluid DB 2090 ST - Hydraulic Oil Change; Ageing of the Hydraulic Fluid

Maintenance and service
110
10.2.2 Hydraulic oil change
An oil change should take place about all 1500 - 2000 operation hours. Discharge
and renew the hydraulic fluid in condition at operating temperature.
WARNING!
Strongly aged hydraulic fluid cannot be improved by refill with
fresh liquid!
10.2.3 Ageing of the hydraulic fluid
The following table gives information on the state of the hydraulic fluid by simple
visual inspection.
Finding
Contamination
Possible cause
Dark colouring
Oxidation products
Overheating, neglected oil
change
Milky turbidity
Water or foam
Water or air penetration
Water separation
Water
Water penetration, e.g.
coolant
Air bubbles
Air
Air penetration, e.g. as
result of oil deficiency or
leaky suction pipe
Floating contamination or
contamination deposits
Solig foreign material
Abraision, dirt, ageing
product
Smell of burn oil
Ageing products
Overheating