I was following the oil life monitor. Having worked with a Mechanical Engineer who was at one point a GM supplier (but stopped because he got sick of GM being cheap) and working with Valvoline at my last job, it is okay to go by the oil life monitor. Quality oils are made to last longer than OLM tells us to change the oil. GM knows this too.
Imo, the problem is the AFM. Even though the fuel injectors and spark plugs are being shut off, there is nothing combating the heat from compressed air. Because fuel not only provides combustion, but helps cool things down too (hence the stoichiometric value of Air:Fuel @ 14.7:1) things in the cylinder are not allowed to cool like they normally would. Things are just heating up more and more, thus allowing the oil molecules to bake on to the cylinder wall and corrode the piston rings. Yes, synthetic oil MAY help because of the uniform size and shape of the molecules, but also due to its higher boiling temp. This question is to what capacity, if any, would running synthetic oil help? Everybody who knows anything understand how important a correct AFR is. The thing with the AFR of AFM is that the numbers are way off with the AFR of N:0, N equaling however much air that is allowed into the cylinder. Imo, a real fix to the problem would either be removing AFM, or doing something mechanically with the cams to prevent the intake valves from opening when AFM is activated.
In case people haven't been paying attention, oil consumption is also an issue for Honda with their V6 in the Pilot that'll shut off 2 or 3 cylinders.
Additionally, GMs oil level indicator only works when you first key the engine on, and not while your engine had been running for awhile. If you drive long distances like I do on occasion you may end up with a situation where you drive several hours with low oil and no warning, thus damaging your engine. Not even my oil pressure gauge gave any indication of a problem. I had even installed a radiator with an oil cooler and used a deeper oil filter. None of it mattered even though my increased oil capacity was approximately 1 quart.
I hope GM is smart enough to not use AFM on the new DI engines coming out with the next generation truck.
