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I used to do oil analysis for the Air Force and I do it for my buddies' aircraft engines. So here's the deal.
One oil sample doesn't tell you much of anything. It's the TREND that counts.
As the engine wears, a little bit of metal goes into the oil at a regular rate. Regular sampling at the same mileage for each sample should show about the same concentrations from sample to sample. If you have a part going bad, the wear in that part accelerates and you will see a sudden jump in the kinds of metal that are in that part. Knowing the kinds of metal helps to identify which part is going bad.
Each individual engine wears each part at it's own rate. So one Saab engine may produce, say 15-20 parts per million of aluminum, while the next person's engine may produce 20-25. Differences may be due to driving style, how long it takes the engine to warm up and a variety of other things, including variations in the parts themselves. So one sample tells you nothing unless some metal is way far out of line from what is typical for that engine model.
Oil analysis won't predict catastrophic failure--it won't tell you a connecting rod is about to break. It only tells you what is going on in parts that are oil lubricated and are subject to wear, say, from friction.
Given that I have access to a spectrometer for oil analysis, do I do analysis for my vehicles? Only for my airplane, where a bearing failure could leave me stranded at some lonely airport a hundred miles from the nearest repair facility.
It would be interesting to hear from anyone on this board who found that oil analysis predicted failure of a part on his/her Saab.
posted by 72.19.4...
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