Oil analysis, for many, has become a matter of faith: Either you "believe in it" or you don’t. Surprisingly, some mechanics and overhaulers don’t. That said, the number of "nonbelievers" continues to decrease as a greater understanding of the limitations and real capabilities of oil analysis become better known.

The reason some overhaulers are reluctant to endorse analysis is that they’ve seen too many examples of engines with serious problems (cam destruction, broken rings, etc.) come into the shop with "clean" oil analysis reports. …