Мне кажется, в части " and so run indefinitely without oil" - имеется ввиду что-то типа "живут, словно двигатель без масла".

Katya, можно попросить чуть побольше контекста... ?

вот побольше:

Some people wouldn't know what to do being alone at times. Finding other
people's company preferable to their own, they begin to feel unhappy and grow introspective. Self-analysis can be carried too far by some; others lose the art of conversation and the ability to give and take - and so run indefinitely without oil. But to the rest of us solitude brings new worlds. When we think and feel, unwatched by man, ideas and feelings come to us, and we get new strength instead of becoming lost in a hurrying world. Ideas and knowledge of oneself that come from peace are the best things in life; these come only from solitude - occasional solitude, of course.