They can run for a very long time; for instance, at the world fair in Milan in 1906, a FRAM engine was started and ran until over one year later.
A crude oil engine is a low RPM engine dimensioned for constant running and can last for a very long time if maintained properly.
Large industrial diesel engines are capable of running on unrefined crude oil, and are widely used in the oil and gas industry.
[1] Additionally, large medium-speed and low-speed marine engines used on ships can also run on crude oil, although significant filtering and processing is often needed before it can be pumped into the engine.
This article about energy, its collection, its distribution, or its uses is a stub.