1- The motivating drive or energy that we need within a situation can be perceived in dreams as an engine (see Car). When the dream seems to concentrate on the mechanical action of the engine, we may need to be looking at the more dynamic pragmatic ways of dealing with our lives.
To be removing the engine could indicate a serious health problem.
2- Depending on the type, the engine can represent the sexual act.
To perceive a diesel or railway engine may be putting us in touch with our own inner power or principles.
3- An engine is symbolic of our own Spiritual inner motivations and drives.... Ten Thousand Dream Dictionary
Psychological / emotional perspective: To perceive a diesel or railway engine may be putting us in touch with our own inner power or principles. Depending on the type, the engine can sometimes represent the sexual act.... Dream Meanings of Versatile