Normal vs. Abnormal Results

What do abnormal results look like?

front view of a car moving on the road

How can we tell if something’s not right? We compare to averages and compare to the trends you’ve established.

For example, we do a lot of BMW M3 samples from owners who are concerned about bearing wear. Below are side-by-side samples of a normal M3 and one with poor bearing wear.

Image of two BMW M3 samples, one with normal lead, one with abnormal lead

Both are 2003 M3’s with the S54 engine. Both have 5,000 miles on the oil, and both are running 10W/60 oil. Lead is just 8 ppm in the sample on the left, and 37 ppm in the one on the right. The engine on the right is suffering from poor bearing wear.

We have averages for most types of systems, and even if we’re seeing something new, we probably have a pretty good idea of how it should be wearing. We take into account things like shorter or longer oil changes, hard use, inactivity, contamination, make-up oil, and the zillion other factors you tell us about. Sometimes we’re stumped about whether something’s out of line…but usually we’re not.

About the Author

Kristin deviated from the family flock by attending Indiana University, earning an English degree. She worked as an editor and writer in Colorado and Michigan before the siren call of Blackstone brought her back to Indiana. Kristin started at Blackstone in 2002 and has since learned to love the intoxicating world of oil analysis. When she’s not working on the website, creating newsletters, doing HR stuff, or writing reports, Kristin enjoys running, swimming, gardening, and working on visiting all 50 states with her husband and kids.

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