Originally Posted By: Linctex
But......
VOA's do not tell the story... it's just an elemental analysis.
They don't tell you what type of chemical formulation exists... just "elements"
"Oh, look at all the zinc!"
You don't know if it's ZDDP or ground up pennies
(or the zinc gear case of the oil transfer pump that fills the jugs is wearing out)
VOA's tell nothing of which basestocks are used in the make-up.
UOA's at least tell you how well an engine is wearing on a certain oil,
or if there are issues from other contaminants.
Really good VOAs, like those found on the PQIA site do give a good indication of the quality of the basestock blend used since they include MRV and NOACK numbers.
UOAs are mainly interesting as an indication of shearing, TBN retention and oxidation, all of which will depend upon the engine in which the oil was run and for how long as well as how the vehicle was used.
They're also interesting as a gauge of just how badly certain engines fuel dilute the oil.