Home › Knowledge Library › How to select a hydraulic oil
How to select a hydraulic oil
A hydraulic fluid is both the lubricant and the power transmission medium. Selection therefore has to consider cleanliness targets and additive chemistry alongside viscosity.
Viscosity and temperature
The pump type sets the permitted viscosity window. For systems working outdoors, the difference between summer and winter oil temperature has to be accounted for — often by choosing a high viscosity index fluid.
Cleanliness target
For proportional and servo valves, the ISO 4406 target can matter more than the product choice. New oil is not automatically on target, so filtering during filling is common good practice.
Additive chemistry
Zinc-based (ZDDP) additives are the norm for wear protection, but some systems favour zinc-free fluids because of filtration behaviour and water interaction. In environmentally sensitive applications, biodegradable fluids are considered.
Price and availability
Contact us for current pricing, stock availability and delivery times for this product group.
Request a quotation