Maintenance: Oil analysis

|  May 03, 2008 |

Editor’s note: There is no standard form for an engine oil analysis report. All labs use their own forms, and while there are broad similarities, to fully understand how your oil analysis service organizes its information ask them to go through an initial report in detail with you.

You know why oil analysis is important: it can help you zero in on the top four engine killers – fuel dilution, soot, coolant and dirt – before it’s too late. But these reports do you no good if you don’t analyze and act on them.

To make sure you’re getting the best value from these reports, look at the following:

Set yourself up for success
If you extract your own oil samples, be sure all your field technicians know the right procedures and why it’s important to follow them. There’s no better case for garbage in/garbage out than oil analysis. If your oil samples are contaminated by the extraction procedure, you’re throwing money away in lab fees.

Make sure you give the lab the correct information about each sample. Most of this information is given during initial setup with your service provider, including the make; model; serial number; location; application (type of job); manufacturer; brand and grade of oil; filter type and rating; and sump capacity of each engine.

Other information needs to accompany each individual sample: the hours on both engine and oil, any recent oil and filter changes, what oil you’ve used to top off with and how much, and the sample date. If any of this information is missing, the lab may note the data gaps, and the resulting report could offer an incomplete picture.

Since oil analysis relies heavily on trending – or charting certain contaminants and elements over time – draw samples on a consistent basis. Manufacturers typically recommend sampling at each engine oil drain interval, usually 250 hours. While you may shorten or lengthen that interval based on the conditions you’re working in and recommendations from your OEM, take a sample at each drain.

If not yourself, designate a person in your organization with maintenance knowledge to manage your oil sample reports. See that they’re staying on top of the total cycle – from extraction to report review to actions taken.

And to provide a benchmark, be sure your lab has an unused sample of the engine oil you’re using.

Verify, verify
Humans can err, machines can be off calibration. Start off your report review by making sure it has the correct machine and component information. Even check to make sure it’s your machine – misidentification can happen. Different engines contain different metals, which becomes crucial in wear metal analysis. A metal level that would pass in one engine might be flagged in another. If the information is wrong, the report will be off.

Note the difference between the date sampled and the date the lab received the sample. If there’s too big of a lag time you may be storing samples too long before shipping, or having problems with your shipping service. Labs should provide reports in one to three days. Any time lags are critical, especially since prompt reporting could prevent engine failure.

Verify the engine and machine hours, since both have a bearing on the analysis. Wear metal limits, for example, are based on the time the oil is in use. Also look at sump capacity, since the total volume of oil is key to trending wear metal concentrations.

Then confirm the oil brand and grade reported is what is actually in the unit. If the machine was topped off with an incorrect oil, the oil signature will be off and engine damage may occur. If this sample was taken at an oil drain, ask the operator to take another sample and verify the oil type. If this sample shows an incorrect oil, change the oil, and refill with the correct oil.

And make sure any comments you’ve made to your service – such as an engine running hot – are noted in the report.

Now look at the alert level
Most reports will give you a quick-glance overall oil condition rating, usually color coded from green (normal) to yellow/orange (abnormal) to red (critical). Then reports are organized in three to four general categories – such as wear metals, contamination and oil condition – which list the numbers for each reported item, such as iron.

This is typically followed by a section that charts out the history of these numbers, helping you monitor oil data trends. Look to see if there are any subtle upward trends, where something may not yet be at a critical level, but will help you identify problems early.

Each oil analysis service organizes their reports differently, so be sure you understand your lab’s methodology.

Put the reports receiving “normals” aside for a moment, but don’t bury them. After you’ve examined the critical and abnormal reports, look at any normal reports on machines that had a previous abnormal report. Confirm your people addressed the previous problems.

Examine the results
Look at the comments section, which will detail any recommended actions. These will serve as your guide as you look through the rest of the report.

Then look at any flagged test number. The lab compares the oil sample against pre-determined limits of particles suspended in oil, expressed in parts per million on any metals present. (See the chart “Diesel Engine Wear Metals Guide” on page 42.) Fuel, soot and water results are reported in percentage of volume. Highlighted numbers show flagged results, indicating the numbers exceed pre-set warning levels.

Your engine oil report may also list viscosity, total base number, oxidation, nitration and sulfation results. (See the “Flagged Problems” chart on page 40.)

Then review the graphs to monitor oil data trends. Trending takes at least three to five samples and offers a picture over the life of the engine. It offers the information you need to act in time.

As you review the total report, be aware that you’re the final filter. You’re the one who knows if items on the report don’t jibe with either the machine in question or your past experience. If something doesn’t ring true, or you want to discuss alternatives to a recommended action, pick up the phone or send a quick email to your supplier. Oil analysis report interpretation requires two-way communication.

Manage the data
With electronic data transfer, there’s little excuse for printed reports gathering dust on a corner of your desk. You pay good money for oil analysis because it red lines engine problems that can cost you big bucks. The more overwhelmed you are with data, the more unlikely you’ll be to act on the solid information it’s giving you.

A number of oil analysis services allow you to slice-and-dice your report information any way you want, and help you create information you won’t ignore. You can get summaries of all alerts, have it organized by a specific job or operator, and get the data downloaded to your own fleet management software. Some services let you manage your reports online – with both current and past reports available 24/7. With online services, you can also have access to your lab results as soon as they’re posted. (See information below)

Take advantage of any training opportunities your oil analysis provider offers. Having in-depth knowledge of all the information provided in these reports will only help your operation.

And act on the information – take time to pull and examine machines with critical reports and schedule downtime on units with less critical reports. That’s what you’re paying for – information you can use.

Manage your information online
Here’s a sampling of the online oil analysis services available, which are free when you sign up with these labs:

Caterpillar
S.O.S Services
www.cat.com
Use the “Find a Dealer” search on cat.com to locate your local Cat dealer. Caterpillar’s web service allows you to print reports, graph results, print sample labels and follow actions taken on a component. View your most current sample information or perform an advanced search by multiple, user-defined parameters.

ExxonMobil
Signum Oil Analysis
www.exxonmobil.com/signum
Provides immediate access to lubrication specialists and customized recommendations. Users can manage equipment registrations and select analysis options and track the status of samples at the lab.

Staveley Services (used by John Deere)
Praxis
www.stavelyfa.com
Offers fleet management, monthly summary and problem summary reports; customizable searches and statistical analysis.

Polaris Laboratories
Horizon
www.polarislabs.com
Receive email alerts or access results online minutes after samples are completed. Set and easily change application preferences and filters to organize information. Use data management software to monitor overall program effectiveness. Breakdown samples by equipment make, model or lube type to pinpoint maintenance issues.

WearCheck (used by Volvo Construction Equipment)
WebCheck
www.oilanalysis.net
Log on to a secure website, search and track your samples, and print management reports. With direct access to all samples, you can modify equipment information at any time, plus modify your equipment database as you buy and dispense of equipment.


Pointers from Polaris Laboratories

  • No matter what the level of wear on a report, never tear down a machine on the basis of one oil analysis report alone. Instead, rush a follow-up sample to the lab to confirm the results and/or use other diagnostic tools at your disposal to further investigate the problem.

  • Review the report comments section before looking at the actual test results since they direct you to the report’s most important information.
  • Make sure you have a well-documented way of taking samples, a procedure so that everyone is doing it in a consistent manner, no matter the machine or technician.
  • It’s important to let the lab know if any oil has been added between samples. If, for instance an engine as a 15-gallon sump, and seven gallons were added, if a moderate rate of wear showed up, the lab might recommend a full-blown inspection because it will know some values have been diluted by the make-up oil.

Source: Jason Papacek, data analysis manager, Polaris Laboratories


Pointers from Caterpillar

  • Set up exactly how you want results reported. With Cat’s SOS program, for example, Cat dealers work with customers to help interpret data. Some customers have any red alert automatically sent to their dealer’s service department, so the department can contact the customer with options, parts and/or rental machines.

  • Sometimes an oil analysis service needs more information to clarify results. Typical questions include whether or not you changed to a different oil brand and/or viscosity, if you changed operators or maintenance personnel, if there was a recent field repair, whether you’ve changed maintenance procedures and if there were changes in the overall machine or job application.
  • Although pre-delivery samples are common, be aware that first-fill oil usually has a high level of chemicals that can throw off an analysis.

Source: David Nycz and Karen Marek, Caterpillar SOS Services


Pointers from ExxonMobil

  • Even though most information is gained by looking at trends, a single sample can have value, especially if it points out an eminent failure.

  • Form a partnership with your oil analysis service provider. Determine whether or not it makes sense for your operation to get additional services. A representative can follow up with you on the most severe reports, and point out the benefits of oil analysis.
  • It just takes a small amount of dirt to kill an engine. If the reports indicate this is a problem, look at your lubricant handling practices, air intake system, filters and hoses.

Source: Joe Harrington, oil analysis technical advisor, and Robert Montevesco, industrial services advisor, ExxonMobil Lubricants and Specialties


Pointers from John Deere

  • You should be able to quickly interpret an oil analysis report. Make sure the reports you receive are logical and easy to read.

  • Focus on the root cause. Don’t examine wear metals first, but instead look first at contamination, which will have an impact on wear metals. Then look at physical properties. If, for instance, you have a low Total Base Number (which measures the alkaline reserve of the oil) and high iron, there’s reason to believe that the low TBN is causing the high iron because of corrosive action.
  • Aluminum and silicon should be shown together on the report, since they represent dirt, the most dangerous of the contaminants. Aluminum, one of the most abundant metals, is common in dirt. Many look at a high aluminum rating and instantly think it comes from inside the component, but that may not be the case.

Source: Diego Navarro, service marketing manager, John Deere Construction and Forestry


Pointers from John Deere

  • You should be able to quickly interpret an oil analysis report. Make sure the reports you receive are logical and easy to read.

  • Focus on the root cause. Don’t examine wear metals first, but instead look first at contamination, which will have an impact on wear metals. Then look at physical properties. If, for instance, you have a low Total Base Number (which measures the alkaline reserve of the oil) and high iron, there’s reason to believe that the low TBN is causing the high iron because of corrosive action.
  • Aluminum and silicon should be shown together on the report, since they represent dirt, the most dangerous of the contaminants. Aluminum, one of the most abundant metals, is common in dirt. Many look at a high aluminum rating and instantly think it comes from inside the component, but that may not be the case.

Source: Diego Navarro, service marketing manager, John Deere Construction and Forestry


Pointers from Volvo Construction Equipment and WearCheck

  • If you receive several reports at once, organize them in the following order: most severe wear conditions first, followed by most severe contamination conditions, and then those with most severe oil conditions.

  • Look for corroboration of a reported condition. For example, if the report indicates severe dirt entrainment solely because of the silica level, look for evidence of wear, or some aluminum indicating alumina-silicate dirt. If the iron and chromium levels are abnormal or marginally elevated, it would be strong evidence of an abrasive contaminant and require action.

Source: Adrian White, Volvo Construction Equipment and Doug Bogart, WearCheck USA

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