Technical Insight
How to choose hydraulic oil
Hydraulic oil selection is not based only on ISO VG. Pump type, operating temperature, pressure, filtration, seal compatibility and OEM guidance should be reviewed together.
Problem
In hydraulic systems, oil is not only a power transmission fluid. It also protects pumps, valves, cylinders and lines against wear, corrosion, foaming and oxidation.
Wrong viscosity may cause efficiency loss, overheating, foaming, slow response or premature wear.
Selection criteria
The first reference should be the OEM recommended viscosity grade. ISO VG 32, ISO VG 46 and ISO VG 68 describe kinematic viscosity at 40 degrees C.
Cold starts, high operating temperature, film strength and oxidation stability should be reviewed according to the real duty cycle.
Checklist
- Machine or system type
- Pump type: gear, vane or piston
- Operating pressure
- Normal and maximum oil temperature
- Current oil and viscosity grade
- Filtration level
- Seal and hose material
- Ambient conditions: dust, moisture, outdoor or hot operation
- OEM recommended standard or approval
Technical support call
Final selection should be confirmed with OEM instructions, the current technical data sheet and actual field conditions.
Let us define the right product for your application
Share machine type, operating temperature, current oil and OEM recommendations; our technical team can help with the right product group and documents.