Originally Posted By: carock
I don't see how the article explains that there is a definite link between wear metals in a UOA and actual wear measured on engine components other than Fe levels trend with mileage. The author of the article seems to draw conclusions about the effects of OCI on engine wear while never performing inspections on engine parts. Does the Ford-Conoco study he mentions disassemble the engines and measure the wear inside?
No, he's saying you can't use a UOA to track wear. Perhaps re-read it with that in mind? That's what the article is designed to explain. As many want to use UOA's on this site as some sort of wear divining rod and that is not their purpose.
They are used to track contamination levels and lubricant life. Fe tracks with mileage, as a contaminant.
And he performed plenty of inspections (tear-downs) during some of his testing. Running Delvac 1 for 90,000Km intervals in OTR trucks for his testing with Mobil. 1.2 million Km parts were measured to be "as new" despite Fe allowing to trend up to 150ppm before condemned and a change necessary.