Does cheaper hydraulic oil do the same job?

Hydraulic fluid has many roles in the smooth operation of a well-balanced and designed system. The foremost role would be that systems demand lubrication to function dependably, and therefore they require efficient hydraulic fluids - ones with optimal viscosity and low power consumption properties.

If your machine is churning or spilling many litres of oil each week it can be tempting to switch to a cheaper alternative to cut costs. But does cheaper hydraulic oil do the same job?


Three types of oil:

There are three main types of hydraulic oil, these are are synthetic, petroleum, and water-based— and each have unique strengths and weaknesses. 


How to select the correct oil?

As a rule, high-viscosity or “thicker” oils cause hydromechanical inefficiencies within the system, for example slower flow. However, this results in improved volumetric efficiency and the thicker oil doesn’t leak so much. On the other hand, low-viscosity or “thinner” oils cause volumetric inefficiencies through leakage, however have the benefit of improved hydromechanical efficiency.

There are three major design types of pumps used in hydraulic systems: vane, piston and gear. Each of these pump designs are deployed for certain performance tasks and operations, and each pump type should be treated on a case-by-case basis for lubricant selection.


Application-based oil selection:

Application-based selection techniques ensure the time spent selecting the proper viscosity, additives, etc was not wasted by simply ignoring the application’s requirements and operating conditions. Following OEM specifications is a great start to ensuring that the correct hydraulic oil is selected, however these are typically for “best-case” scenarios, and ignoring the reality can often lead to failures down the road. Therefore, application and operating factors should be taken seriously.


Cheap oil – occasionally it's OK, but often it's not:

When buying cheaper hydraulic oils, many will lose efficiency either due to loss of flow or volumetric leakage. Typical monograde oils have poorer control over their viscosity, as they are either unable to flow well in colder conditions, or are depleted due to leakage in extremely hot conditions. Thus, in conditions that vary widely between very hot and very cold, problems arise. 

Additionally, due to the larger amount of coarse particles in cheap oil, accelerated wear is often noted. Hydraulic oil needs to meet OEM cleanliness specifications to help avoid damage to critical components throughout the hydraulic system, including servos, directional valves, hose, and pump parts. 


Why are you churning through so much oil?

If you waste a lot of hydraulic oil, getting a cheaper oil is not always the solution - reducing the spills is. Identifying the hoses (or hoses) that are causing the problems and getting to the root of the problem is always better for your equipment in the long term. This might mean reinforcing the hose, e.g. using four braided hoses instead of two braided, applying sheathing, etc. It could also mean rerouting the hose to prevent bursts, or pro-actively replacing the hose.


As always, if you do not have the proper training to make such a decision, it can be a good idea to talk with a technical specialist about the most appropriate hydraulic oil for your equipment. Our team can supply and recommend application-based hydraulic oil solutions. Please get in touch to speak with our sales team.