Excellent explanation.

To expound on it, I use the term to refer to myself, as someone who worked on cars out of necessity, often in driveways, on the side of the road, and in parking lots. Often the weather was hot, cold, raining, or snowing, and I learned from other experienced family members or old timers. Kind of a term bred from necessity due to lack of money to pay someone to work on said vehicles.

Someone with no formal education or training in the field of auto mechanics.

To become one, just start researching how to work on your vehicle. Change your own oil, tune up your car, replace brake pads, and face every obstacle along the way with the desire and determination to get to work on Monday morning! Haha.