As per UOA, the gasoline engine was harder on the additive pack than the Dmax.
The attraction of using XW40 engine oils in all my vehicles is that all except the Dmax, they can go 7,500 miles or more with out adding oil.
In the same using XW20s as per oil cap on 2 X 2013 Matrix, I would expect 1 liter per 1,300 miles consumption. (The 2015 5.3s likely about the same)
The above 5.3 is a 2013, 5W30 Dexos on the oil fill.
A short winter interval on a non-Dexos 5W30 was a disaster, used a liter in 3,000 miles in the 5.3 and turned the inside of the engine parts in the Toyotas brown.
Summer of 2014, 15W40 CJ-4/SM went into everything. The oil cleaned up what the 5W30 left behind and none of the vehicles need oil added between changes.
I had the 15W40 from the 2013 5.3 tested, then a year later with the same brand of 5W40 and a M1 212 filter.
Poking around the South African Toyota site I noticed 15W40 oil fill caps on everything.
Gotta get me some of those.
I test the oils to see how far they will go, instead of trying to determine a wear trend or initiate a contest between one oil over another.
Here is why:
Oil "A" might show lower iron than oil "B", but for all I know ALL the iron in oil "A" came from the top ring reversal point, while most of the iron from oil "B" came from the bottom of the cylinder at the oil ring reversal point.
The high aluminum in my Dmax using SAE 30 was from 150 cold winter starts, not a deficiency in the engine oil.
The oil was good to go much further when I chickened out and drained it.
Back to the 2013 5.3L.
The duty cycle is 99% highway, once in a while it will log a 4,500 mile month.
I would bet with 15W40, the average bulk oil viscosity is lower than a short hopped city church going grocery getting truck with 0W20 in the crank case.
My Dmax has 54,000 miles on it, but only 1335 hours. That is why I can get away using mono-grades, weather permitting.
Viscosity is only half the story. If I use an engine that will go OLM with out adding, the additive package better go the distance too.
For example if an engine spec'd to run on XW20, consumes a quart every thousand miles with X additive package, using 20W50 to halt oil consumption with X additive package would be foolish, not from a viscosity argument, but from an additive depletion standpoint.
Once again, depending on circumstance, weather and duty cycle, the engine with the 20W50 may have a lower average bulk oil viscosity than the short hopped one with 0W20.