Oil is a liquid that can be thick or thin.
oil slicks arent very thick or very thin it is about a half of a foot
Engine oil too thin.
No.
thin air
Thin oil zone below a gas cap
Normally there is no need to thin oil based paint if you are applying it with a brush. If the oil based paint is old, it may have thickened over time and in that case you can thin it until it is at a consistancy which is easy to brush and gives good coverage. If you are spraying the paint you may want to thin it so it sprays easier from the gun. Thin then test and do it agoin until it sprays evenly from the gun. Normall "oil based" paints when thinned are with paint thinner. However always read the label on the paint for any instructions concerning thinning.
Whatever oil you buy for the car(check for recommended oil thickness)will do fine.
Why would you?
Lacquer thinner will thin many types of oil based paint, but not all. -Experiment with a little first.
Usually a mix of Tung Oil and Boiled Linseed Oil with mineral spirits to thin.
kerosene is a thin oil that was used in 1849 to light oil fuled lamps.
it thins as its molecules spread apart and increase the volume of oil and as matter can neither be created nor be destroyed, it just expands and becomes thin