Oil Analysis Blog-

Oil Analysis Blog

The Thick and Think of Viscocity


If you have a gearbox with a manufacturer’s nameplate instructing you to use the American Gear Manufacturer’s Association (AGMA) #4 viscosity oil at a given operating temperature, or if it specified a 750 SSU viscosity oil, would you know exactly what viscosity oil you need? If your grease application specified a base oil viscosity of 220 cSt for a given operating temperature would you know which of your greases might fit that specification, if any?

Does it really matter? Oil is oil, grease is grease, and more is better, right?


The importance of proper oil viscosity in your large array of equipment and the varying lubrication regimes they present is one of the most important maintenance practices one can focus on in their facilities. Viscosity is the most important physical property of a lubricant, and viscosity is the most important specification for a lubricant. Along with this, viscosity is the easiest thing to mess up!

A simple definition of viscosity is the thickness of an oil. While this is the most common understanding of viscosity, a more technical definition of viscosity is a measurement of the oil’s internal resistance or its resistance to flow by gravity. Viscosity is what carries the load, separating surfaces in relative motion from touching, thus reducing friction and wear, extending equipment life.

Viscosity should always be measured at a given temperature. Normally viscosity is inversely proportional to temperature, meaning as the temperature of an oil increases, its viscosity generally will decrease.

Stating an oil’s viscosity is found in many different formats depending on the application. The International Standards Organization (ISO) is the universally accepted method for stating oil viscosity (ISO VG) through-out industry (ISO 3448). This ranges from an ISO VG 2 to an ISO VG 3200. ISO VG is stated at 40°C.

AGMA specify grades an oil’s viscosity for industrial gear applications, also at 40ºC. The AGMA uses a #1 through #8A designation.

SUS – or – SSU is not in use much anymore, but you may still find it referenced on an older gearbox nameplate or an OEM (original equipment manufacturer) manual. This stands for Saybolt Universal Seconds – or – Saybolt Seconds Universal, you’ll see it stated either way.

Society of Automotive Engineers (SAE) Crankcase and SAE Gear classifications are different yet. 0W, 5W, 10W, etc., and straight weights 30, 40, and 50 are designations for crankcase oils, while 70W to 85W and 80 to 250 are designations for automotive gear oils.

If all of this is making sense, I commend you. You are likely on top of your game and know exactly which oils and viscosities belongs in each application throughout your facility. But if this sounds like a foreign language that you do not understand, it’s okay, as long as you now realize that your equipment may be in jeopardy of shorter life cycles and there is potential for cost saving improvements that will greatly enhance your equipment’s reliability.

This article was originally posted at pioneer-engineering.com and Reliabilityweb.com.

Six Ways To Improve Your Oil Analysis Program


The success of any lube analysis program is often dependent on proper planning and execution.  Much like an airline flight whose crew must perform a detailed checklist of activities before the plane is approved for takeoff, a lube analysis program should be designed with various checks and balances, standards, procedures, and other verification to ensure its success.

To ensure the success of your program consider these six best practices:

  1. Establish Proper Sampling Procedures: Sampling is the most important part of  any lube analysis program and the quality of your samples is vital to the success of your program.  It so important to get consistent samples from the exact same place every time a sample is taken. If your sampling methods are inconsistent then you will most likely have inconsistent and inaccurate test results.  To combat this, consider standardizing your sampling method and train all samplers to properly use the method you choose.
  2. Avoid Delays In Receiving Results: You should ship samples as soon as they are collected.  If you wait to send samples to the lab you run the risk of not catching potential problems that can be detrimental to your plant’s operations.
  3. Learn How To Interpret Test Results: Too often in lube analysis the failure of a program can be attributed to  the lack of interpretation of the conditions report and an inappropriate response to the results. When this happens, valuable information is lost.  Without a solid understanding of the purpose of lube analysis and the ability to interpret test results they can not be expected to carry out this duty.  Your lab should also be adept at interpreting results.
  4. Communicate With Your Lab’s Analysts: In order to create and maintain a world‐class lube analysis program, you need to have the support and dedication of your lab.  You should strive to develop a relationship with your lab analyst and have the confidence that you can call upon them at any time to discuss concerns about your equipment or overall program.  This can only be possible if your lab is committed to you as well.  Your analyst needs to be familiar with your equipment, and more importantly, they need to know your goals and expectations for your program.
  5. Establish Adequate Performance Tracking: A true predictive maintenance program should be more proactive than reactive.  Your program should emphasize routine planned activities focused on monitoring and controlling root causes, which will ultimately diminish the frequency of machine failures.  Many programs focus only on measuring machine conditions and completely miss the opportunity to measure the generated benefits their program has produced.  Tracking such things as machine availability, replacement parts costs, labor hours on planned and unplanned activities, and lubricant consumption are also important.  In order to do this you should identify benchmarks early on so you have something to rank improvements against.
  6. Give Your Leader Authority:  You need the person in charge to be a leader – someone who is knowledgeable, experienced and motivated.  But even with the right person in place there are still many obstacles that need to be avoided.  One of the toughest and most wide‐spread obstacles is a lack of authority.  Many times people that are excited about their position, but they lack confidence to take action because they have no authority.  If you are training a new person in a lube analysis program, be patient with them.  Remember that training generates confidence.  Be sure to invest in their training so they have the confidence to make the right decisions, and empower them to take action.

To learn more ways to improve your program, click here to check out TestOil’s eBook on the topic.

Know the Proper Base Number of Your Oil


“What base number should oil have?”

The base number (BN) is a property that is more associated with engine oils rather than industrial oils. It can be defined as the oil’s ability to neutralize acids that are produced during use. The higher the base number in the engine oil, the more acid it will be able to neutralize during use.

New engine oils usually have a range of 5 to 15 BN. As oil is used in service, it becomes contaminated with acids, causing the base number to drop over time. By using oil analysis for your engine oil, you will be able to track the BN of your oil and determine how much life is remaining. Once the base number drops below 3, this is considered too low and should trigger an oil change for your engine.

The most common reasons for a drop in the base number are related to low-quality fuel and oil oxidation. During combustion, a low-quality fuel with high sulfur content can produce sulfuric acid, which attacks the oil and causes a drop in the base number. Oil oxidation as a result of the engine overheating or an attempt to extend the oil drain interval is another reason you may see a drop in the BN.

The acid number (AN) is a property that is generally more associated with industrial oils than engine oils. It is the amount of acid and acid-like substances in the oil. As mentioned previously, oil oxidation is one of the main producers of acid.

As oil is used in service, acidic components are generated and build up in the lubricant, with the end result being an increase in the acid number. A high acid number represents the potential for corrosion, rust and oxidation. It can also be a signal to perform an oil change. Again, by using oil analysis, you will be able to track the AN of your oil and schedule oil changes.

You also will need to set a critical limit for when the acid number reaches a certain number in order to schedule an oil change. This critical limit will be dependent on the type of oil being used. Typically, for R&O or light-duty oils, a maximum acid number limit of 2 is appropriate. For anti-wear and extreme pressure (EP) oils, an AN limit of 4 is a good starting point.

This article was taken from Machinery Lubrication.

Oil Analysis and its Role In Equipment Reliability


Selecting the proper lubricant, along with careful maintenance of that lubricant, is essential to ensure adequate protection to any machine. Proper lubrication is defined as a correct amount of the correct lubricant at the correct time.

Maintaining a lubricant means ensuring that it has the correct viscosity and the necessary additives for the application. Steps must be taken to keep the lubricant clean and serviceable. Oil analysis is the most effective way to prolong the useful life of lubricants, while maintaining maximum protection of equipment.

Oil analysis tests reveal information that can be broken down into three categories:

  1. Lubricant condition: the assessment of the lubricant condition reveals whether the system fluid is healthy and fit for further service, or is ready for a change.
  2. Contaminants: increased contaminants from the surrounding environment in the form of dirt, water and process contamination are the leading cause of machine degradation and failure. Increased contamination indicates that it is time to take action in order to save the oil and avoid unnecessary machine wear.
  3. Machine wear: an unhealthy machine generates wear particles at an exponential rate. The detection and analysis of these particles assist in making critical maintenance decisions. Machine failure due to worn out components can be avoided. It is important to remember that healthy and clean oil leads to the minimization of machine wear.

Lubricant condition is monitored with tests that quantify the physical properties of the oil to ensure that it is serviceable. Metals and debris associated with machine wear are measured to monitor equipment health. Some tests target specific contaminants that are commonly found in oils.  It is imperative to select the proper blend of tests to monitor the machine’s lubricant condition, wear debris and contaminants in order to meet the goals of successful oil analysis.