It is known that some oils are eaten up by the engine, at a rate of up to 1L per 1k miles or so.
Are ester-based oils (like Redline 5W40) less or more likely to disappear from the oil pan after going a certain number of miles (e.g. burn out together with gas into exhausts), compared to non-ester-based fully-synthetic oils?
It depends more on the thickness of the oil than it's composition. Oil is lost from the engine through leaks and burning.
Both occur as the engine wears with age, and the tolerances between the components increase, allowing the oil to seep past various seals in the engine. Some of it 'escapes' to atmosphere, for example through the crank seals, and some gets into the cylinders, and is burnt (leading to blue smoke).
In general, a thinner oil will be lost more, as it needs less gap to get through - hence why older and more agricultural engines, with their less-precise tolerances, tend to use thicker oils.
