Why is it cheaper to completely fill your tank in one go than to fill it in small increments over a long period of time?

Question

I don’t know if it’s true but it’s what I have been told by a few different people.

In: Economics

Answer 1

In all reality, it doesn’t matter either way. The amount you save due to lack of vapor space will be offset by other things, and is so miniscule anyways that you wouldn’t be able to measure it without very careful testing.

Don’t constantly run your tank under 1/4 though, as fuel pumps are cooled by the fuel around them, and at 1/4 tank there’s hardly any fuel around them and they will wear out quicker.