Used Engine Oil Analysis – Test 2

In the first Oil Analysis article we tested an oil that had been in service for 15 months. During that time we racked up 8000 miles of spirited driving. If you haven’t read that article it can be found by clicking here. Please take a look at it as it explains how we go about the process of used engine oil analysis.

In this Used Engine Oil Analysis – Test 2 article, the oil being tested is a nationally known brand of synthetic 5-20 that is advertised to be good for one year or 25000 miles whichever comes first under normal conditions. The test vehicle is a 2009 Honda CRV with 54000 miles on the odometer. It is your typical “normal conditions” grocery getter.

I originally thought that the oil we are testing had accrued 18000 miles of use during 10 months of service. However, upon double checking with the owner I found out that the oil under test had been in service for 17 months and 23000 miles! This clearly exceeds all manufactures extended drain interval recommendations. The last oil change date and mileage had been forgotten, and leaving the oil in service this long was not intentional.

A sample of the used oil was taken and sent to Oil Analyzers Inc. to be tested for viscosity, corrosion potential, wear metals, and beneficial oil additives. Click here to view a PDF brochure from Oil Analyzers Inc. It describes the Oil Analysis program. Starting on page 8 take a look at the “Reading the Fluid Analysis Report” instructions. It shows exactly what the report looks like and it explains the test results.

The results from analyzing a 5-20 viscosity oil with 17 months and 23000 miles of use in a 2009 Honda CRV are as follows:

  • Very low levels of wear metals were found to be present. Wear metals are described as the metal components within the engine.
  • A normal level of the contaminant metal Silicon was present. Contaminate metals are described as dust and dirt. Silicon sources are listed as abrasives (dirt, Alumina Silica), seals and gasket material, lube additive or supplement, and/or environmental contaminants.
  • The level of the multi-source metal Boron was slightly low. Multi-source metals are described as additives.
  • The viscosity was out of specification. The oil had thickened and the viscosity moved into the range of a 30 W.
  • The TBN or Total Base Number, which is used to determine if the oil is becoming acidic, was found to be very low. The oil had lost over 80% of its original TBN value.

Clearly the oil was past its useful life. The depletion of the TBN value beyond 80% of its original number is the greatest concern reported here. This oil was in service for 17 months and TBN levels decrease the longer an oil remains in service. I suspect that is why the TBN value is very low. The oil manufacturer states a 12 month maximum service interval and we exceeded that by 42%.

The oil and filter were changed at the time the sample was taken without waiting for the test results to come back. Once this new oil has been in use for 12 months it will be analyzed and I’ll post the results here in another article.  At that time we will be able to compare the test data between 12 and 17 months of service. Hopefully we will be able to make some correlations between the time in service and mileage, and the effects they have on oil degradation.

The moral of this story is to keep good records and set at least one reminder to change your oil. Use your cell phone, computer calendar, write a note, or anything else that will alert you that it’s time for a change!

MyAmsoilGarageI use and recommend a free web based application called My Amsoil Garage to keep track of all my vehicles maintenance activities. The My Amsoil Garage app allows you to track any maintenance item for an unlimited number of vehicles. One of its nicest features is the ability to set up and manage email reminders for scheduled service activities, like oil changes. There is also a handy lookup tool for all your car and motorcycle manufacturers’ recommended lubricant viscosities and capacities. This application is free and there is nothing to install as it is web based. Check out the My Amsoil Garage by clicking here. I’m sure you will find it very useful.

Picture of the Oil Analysis Kit contents


If you would like to have your oil analyzed you can purchase a kit from Oil Analyzers Inc. by clicking here.

Disclosure: This is an affiliate link and I will receive a commission if you make a purchase.




Once again if you haven’t read the first Oil Analysis article it can be found by clicking here.

I hope you found this Used Engine Oil Analysis – Test 2 article informative. Look for more articles on lubrication to follow. Remember to give the My Amsoil Garage a try. It’s useful and it’s free!

I value your comments, suggestions, and opinions. Please leave a comment below.

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    2 Responses to Used Engine Oil Analysis – Test 2

    1. Tom Peszek January 10, 2015 at 8:56 pm #

      Great article, and I’m looking forward to the next 12 month oil analysis to see how much the data improves!

      • Richard Horton January 11, 2015 at 8:36 pm #

        Hi Tom,
        We won’t have to wait 12 months for another oil analysis. I’ll be analyzing the oil from the first article again in a few months. At that time the oil from the FR-S will have been in service for 12000 miles over a 21 month period. I’m interested to see if we can correlate any data between miles of use, length of service, and oil degradation.

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