[Hib Halverson]

One thing you have to remember about spectrographic oil analysis is that what you see in the results is "cumulative" because the stuff that oil analysis analyzes is too small to get trapped in the filter.

So, if you change the oil every 3000 miles and see 25-ppm iron you're in much worse shape than someone who changes oil every 15,000 miles and sees 25-ppm iron.

When you say your engine doesn't use any more oil that other 90s...are you talking about 90s with or without exhaust valve stem seals?

Lastly, iron can come from more places than just liners.