An engine is symbolic of our own Spiritual inner motivations and drives. 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. The motivating drive or energy that we need within a situation can be perceived in dreams as an engine. 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 health problem, perhaps putting our health at risk by overdoing it. You might also wish to consult the entries for Car, Engine, Piston and Transport.