The Benefits of Comprehensive Hydraulic Fluid Testing

Unfortunately, there is no steadfast rule that will tell you exactly when it is time to change your hydraulic oil. The quality of your oil, the type of application you are running, and the environment in which you are working can all dictate how long your hydraulic fluid will last. Having an accurate picture of when to change out your hydraulic fluid is important because it can become costly and wasteful to prematurely change out fluid or filters that have very little contamination; it can also be costly and damaging to continue running an operation with contaminated fluid. That is where a comprehensive fluid analysis comes in.

Conventional wisdom dictates that your hydraulic oil should be tested, at the very least, quarterly. For systems that are exposed to other elements, including marine hydraulic systems, testing may be more frequent. Some operations that require their own testing kits will have an even better handle on preventative maintenance by finding contamination well before the oil needs changing, or worse, once a failure analysis is needed. While DIY testing is an excellent line of defense for your hydraulic system, additional lab testing offers an in-depth analysis of more than just contamination severity, but also the type and source of contamination.

A lab analysis can give you information on three things: degradation, wear, and contamination. This information is deduced by testing the following:

• Particle count: How clean is the oil?
• Additive depletion: Are anti-foaming or anti-wear additives degraded?
• Viscosity: Have particles increased viscosity, making the oil more difficult to pump? Has the pour point changed significantly?
• Metal wear and contamination: are your machine parts wearing down and causing debris?
• Water contamination: Is water present, causing a decrease in fluid viscosity?
• Changes in acidity: is oxidation leading to increased corrosive acid count?

Spectrometric analysis for additive and trace metal content, particle isolation for particle identification, and Energy dispersive X-ray (EDX) analysis for exceptional contamination are all common tests performed by laboratories that provide much more information than an in-house, portable particle counter. Though some available technology offers elemental analysis of contaminants, portable particle counters often give information limited to the number of particles and their size.

Furthermore, the analytical techniques in a lab have the added benefit of expert knowledge, and that knowledge frees up the ability to skirt costly and time-consuming employee training in your operation. The process is as simple as taking a sample while the system is operating, either from a valve on the system’s return line just before the filter, or in the midpoint of a reservoir, away from its walls and base. Once the lab receives and analyzes the sample, a thorough report will be returned with helpful guidance and warning signs for your hydraulic system.