Used Engine Oil Analysis – Test 3

This article is the third in a series about Used Engine Oil Analysis. In it, we’ll take a look at the results of testing an oil that was used for 10,500 miles over a 21 month period.

This is the second time that we have tested this used oil. In the first test, the oil was used for 8000 miles over a 15 month period. At that time the test results revealed that the oil was still serviceable. The recommendation was to leave the oil in service and “re-sample in 3,500 miles or 65 hours.”

If you haven’t read that first article, please take a look at it as it explains how we go about the process of used engine oil analysis. It can be found here by clicking Used Engine Oil Analysis.

After reading the results of the first test I did not change the oil. I did however, change the filter at that time because the report had shown “a moderate level of the contaminant metal Silicon was present.” Silicon was described in the report as dust and dirt. I opted to change out the filter with an Amsoil synthetic media type, and run the same oil for another 2,500 miles.

After the 2,500 miles had been reached, I took a sample of the oil and sent it to Oil Analyzers Inc. To learn more click here to view a PDF brochure from Oil Analyzers Inc. It describes their 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, used for 10,500 miles over a 21 month period in a 2013 Scion FR-S are as follows:

  • Low levels of wear metals were found to be present. Wear metals are described as the metal components within the engine.
  • A moderate 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. Note: Silicon levels increased from 39 to 43 (ppm) since the last test of this oil.
  • The level of the multi-source metal Boron was slightly low. Multi-source metals are described as additives. Note: Boron levels decreased from 131 to 97 (ppm) since the last test of this oil.
  • The viscosity was found to be well within specification.
  • The TBN or Total Base Number, which is used to determine if the oil is becoming acidic, was found to be moderately low.

The comments from the Analysis Report are as follows:

“Flagged data does not indicate an immediate need for maintenance action. Continue to observe the trend and monitor equipment and fluid conditions. Base Number is MODERATELY LOW. Silicon is at a MODERATE LEVEL; SILICON sources can be abrasives (dirt, Alumina Silica), seals and gasket material, lube additive or lube supplement, and/or environmental contaminant; Boron is slightly low for this lubricant. Lubricant and filter change acknowledged.”


I had changed the oil and filter when I took the sample for this test. I didn’t wait for the results because I felt as though after 21 months of service, the oil deserved to be changed. However, after reading this report it is clear that the oil was still suitable for use.

After studying the results from this test, I have put in place a 15,000 mile, 24 month drain interval on this oil and filter. That is of course, if the driving conditions and annual mileage remain the same on this vehicle.

By testing the oil and keeping it in service for an extended period, I have saved time and money. Not to mention the work required to change the oil.

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.




I hope you have found this article helpful. Look for more articles on lubrication to follow.

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

It’s all about the car!



Be Sociable, Share!


    2 Responses to Used Engine Oil Analysis – Test 3

    1. Bill Cox July 28, 2015 at 12:57 pm #

      Richard, Thanks for the information on the last two oil tests. I’m defintely impressed with the results especially regarding the relative state of the oil after exceeding the normal 6 month 6000 miles which is what a typical dealer or Oil/Lube center would typicall recommend..

      Thanks for all the info.. Great site – Keep up the good work..

      • Richard Horton July 29, 2015 at 2:54 pm #

        Hi Bill,

        Thanks for the comment.

        I was skeptical when I first heard about extended drain intervals, so I decided to put the claims to the test and have my used oil analyzed. I must admit I was a little nervous when the oil was approaching two years of service and I still hadn’t changed it yet. NOTE: (I had changed over to a synthetic media filter during the test.) This last test showed that the oil was still protecting the engine, and it didn’t need to be changed yet.

        For under $20 this oil analysis kit has more than paid for itself. It has saved me the money, time, and the effort of an oil change. Plus, I now know that I can run this oil in my FR-S under the same conditions for around two years, which in my case will be about 15,000 miles.

    Leave a Reply