Is Amalie motor oil any good, or just cheap synthetic?

How 5W-50 full synthetic actually protects an engine

Here's what the numbers on the bottle are actually telling you. The 5W is the cold start rating, how the oil flows through the pump at low temperature; the 50 is the hot rating, how thick the film stays once the engine's at full operating temperature. Most daily driver oils top out at 30 or 40 on that second number. A 50 weight full synthetic is built to stay thick under heat, which matters when the engine has more clearance between the bearings and the crank than it did new, or when it's working hard: towing, track days, sustained heat. That's the whole reason 5W-50 exists as a grade, and it's why an older or high performance engine calls for it by name in the manual while a modern commuter engine never will. The full synthetic base stock is doing a second job underneath that. Synthetic molecules are uniform where conventional crude based oil is a mix of different sized molecules, so the oil resists breaking down and thinning out as heat and mileage stack up between changes. Amalie's flash point sits around 224 degrees Celsius, the temperature the oil starts giving off vapor instead of holding together as a liquid film, and higher is a decent proxy for how much heat it can take before it starts to fail on you. Put those two things together and you get an oil built for load and heat, not for squeezing an extra half mile per gallon out of a small daily driver engine. Twelve quarts in the case means it's priced for someone doing their own changes on a schedule, not buying one bottle to top off between services.