Originally Posted By: Oldtom
I would think the OLM would give more weight to the short tripping and reduce the remaining oil life.
I find it strange that after 6,000 miles and short trips the OLM is still at around half done. In 2012, GM was requiring the use of at least a semi-synthetic blend (the worst possible dexos1 oil). Still, you're talking about going maybe, I'd guess, 10,000 miles and 1.75 years on an oil change.
Maybe it would help to see some actual DSC/TAN/TBN/PIN results using the GM OLM.
http://www.machinerylubrication.com/Read/77/gm's-oil-life-system-improves-timing-of-oil-change
"In Figures 4 a-c the results of four analyses, as indicators of oil degradation, are plotted as a function of distance traveled for the three test vehicles. The four oil analysis tests are:
1. Total Acid Number (TAN)-Concentration of acid constituents in the oil from oil oxidation and combustion products.
2. Total Base Number (TBN)-Depletion of overbase detergent additive.
3. Differential Scanning Calorimetry (DSC)-Approximates the remaining life of the antioxidant (residual oxidation induction time).
4. Pentane Insolubles (PIN)-Concentration of carbon soot and sludge."
The PIN was really ramping up on Vehicle A following the OLM.
This shows the OLM can miss a bit. Its good, yet you probably can avoid that last upturn in PIN with oil that is better than it has to be to just meet dexos1.