When you get your annual physical, blood and urine tests are usually part of it. Your doctor can tell a lot about your health by finding out what is in your vital fluids.
It's the same with your machinery: What's in the lube oil, coolant and hydraulic fluid can reveal vital information about your equipment's health. And it doesn't hurt to test your fuel, as well, to see if you're "feeding" your machines a suitable diet.
You don't need a big equipment fleet to make fluid analysis worthwhile, and you don't need a fancy local lab to take advantage of the service. Equipment manufacturers like Caterpillar and John Deere offer analysis service through their dealerships, and some independent entities, such as FRAM, provide it as well.
Not about the oil
One misconception about fluid analysis is that its purpose is to assess the condition of the fluid, such as to help decide how soon to change it out. It does serve that purpose, but only secondarily. The real purpose is to detect conditions in the fluid that indicate trouble with the equipment before premature wear or a breakdown can happen.
For example, high levels of metals in engine lube oil can indicate that premature wear is occurring. The analysis results can provide clues to the type of wear (corrosion, cavitation, abrasion) and exactly what parts are wearing.
Similarly, the presence of silica (sand) in oil may indicate a defective air filter.
The results of an oil, coolant or hydraulic fluid analysis may help decide whether to extend or shorten the changeout interval, or keep it the same.
But the more important outcome is to indicate a potentially serious issue that you can then diagnose and solve. When used effectively, fluid analysis can help you:
Make your machines more reliable
Save on maintenance and repair
Schedule maintenance optimally
Save fuel
Sustain peak machine performance
Looking into the oil
The most commonly analyzed construction machine fluid is lube oil, simply because what happens to the oil can affect so many internal engine components. Here are some conditions that analysis can show you:
Contamination. Unwanted substances can get into the oil from inside or outside the engine and even from the oil itself. Wear particles from bearings and cylinder components can enter the oil and grind down other metal parts. Water and coolant can escape into the oil through worn-out seals or packings – antifreeze in oil is highly destructive. Sand and grit can enter through openings in the system. Contaminants even can come from the oil itself in the form of soot or sludge.
Oxidation. At high temperatures, oil molecules will react chemically with oxygen, forming hard, abrasive particles and making the oil more viscous (thicker), so that it becomes difficult for the engine to pump it throughout the system.
Loss of additives. Quality oils contain alkaline additives that help neutralize destructive acids, along with rust and corrosion inhibitors and
chemicals called dispersants that keep damaging substances in suspension until the oil is changed.
Acidity. Acid in oil will attack metal components and significantly accelerate wear. A typical oil analysis measures the acid content of the oil as well as the amount of acid-neutralizing additive remaining.
A basic oil analysis monitors the oil for wear and contamination. The report typically lists individual metals detected and their amounts, along with levels of water, viscosity, fuel dilution and soot. A more detailed analysis can add total acid number (TAN), total base number (TBN) and oxidation/nitration testing to see if the oil is suitable for continued use.
The analysis report typically includes observations about the oil's condition, the equipment's condition, and any maintenance and service recommendations.
Examining other fluids
Some equipment owners look beyond lube oil and have other vital fluids analyzed. Specifically:
Coolant. Coolant problems cause, by some estimates, as many as half of engine failures. If a coolant has the wrong chemical makeup for the temperature in which the machine operates, then corrosion, erosion, pitting and scale formation in the cooling systems will accelerate. Corrosion can damage cylinder liners, heat exchangers, radiators, and other parts. The analysis detects conditions including metal corrosion, combustion gas leaks, contamination, overheating problems, and coolant chemical breakdown.
Fuel. Diesel fuel analysis can pinpoint possible causes of fuel filter plugging, engine smoking, power loss, poor injector performance, sticking valves, and other conditions. It can also determine whether the fuel sulfur content meets the machine maker's cleanliness specifications. If not, the machine warranty may be in jeopardy.
Hydraulic fluid analysis. Dirty hydraulic fluid can quickly wear down your machine's hydraulic system. Analysis helps make sure the fluid is clean and functioning properly and points the way to maintenance issues that need addressing.
Making a commitment
Oil or other fluid analysis is not something to be done once and forgotten. It constitutes a program to follow regularly so that you can detect trends in fluid and engine condition and, if need be, change maintenance and operating practices. Experts generally recommend oil analysis at each planned maintenance interval, coolant analysis at least once a year, and diesel fuel analysis as needed for winterizing the machines or checking the condition of storage tanks.
It is also essential to draw fluid samples properly. The dealership or laboratory you choose will provide instructions for taking samples without contaminating them, so that the lab tests deliver reliable results.
Fluid analysis is a useful program that can quickly pay dividends. Many users find they easily recover the modest costs of sampling and lab testing in better machine performance, longer machine life, and smaller repair and maintenance bills. O
