Oxidation question

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Staff member
May 27, 2002
Guelph, Ontario
Is it possible to have an oil analysis where the viscosity of the oil did not thin out or thicken up, and the oxidation is high?

And in the opposite situation, is it possible to have no oxidation at all, but yet the viscosity has changed.

In other words, is viscosity change and oxidation always directly comparable? I guess I'm trying to figure out if there is a way to figure out oxidation based on oil analysis reports where the oxidation is in question? (such as my last report which showed 37% oxidation in 740 miles, which I believe is simply not possible since the oil's viscosity did not change so soon)

Originally posted by darrenc:
Wouldn’t fuel dilution come into the equation too?

True, but for the purposes of this question, let's just say that there was less than 0.5% fuel in the oil, so it is not a factor.
Another oxidation related question---

If the oil thins due to shearing and concurrently thickens due to oxidation, the viscosity is still OK, but is the protection still there?

Patman, lube oxidation rate/level not always directly correlated to viscosity change . Depends on what part of lube is oxidizing and why.

Variablity is the problem in establishing rules of thumb for accurate oil analysis interpretation,especially PCMO"S.
Another question,What or how many different parts of an oil can oxidize, and what would be some clues as to why

If I may, how does LC interfere with the oxidation process,I should be getting some very soon. Odis is an extremely nice person to talk to by the way

1. The LC contains some ingredients that inhibit most oxygen molecules from forming peroxides, those chemicals that contribute most to oxidation.
2. LC contains a special solvent that depolmerizes the sludge and the sludge "precursors," those peroxides and nitroperoxides that contributes to oxidation.

The base oil and any additive components that are subject to oxygen binding may oxidize over time.

This the great thing about Moly, Antimony, and ZDDP, they are also anti-oxidants as well as AW additives.
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