I hate to tell you but that Rotella 5w-40 synthetic, isn't a real synthetic.

Its basicaly a dino oil, group 3. True synthetics like Mobil 1 0w-40 and Amsoil are group 4.

So you can't blame the burning on synthetic, I suspect since you went to a much lighter oil you are burning it.

If you want to test this run Mobil 1 15w-50 next change, this is a true synthetic and similer in weight to your old oil. I suspect your oil burning may go away or be greatly reduced by this.

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2016 Corvette Stingray 2LT
1969 280SE
2023 Ram 1500
2007 Tiara 3200