Definition of oil
An oil is any neutral, nonpolar chemical substance that is a viscous liquid at ambient temperatures and is both hydrophobic (immiscible with water, literally "water fearing") and lipophilic (miscible with other oils, literally "fat loving"). Oils have a high carbon and hydrogen content and are usually flammable and slippery.
The general definition of oil includes classes of chemical compounds that may be otherwise unrelated in structure, properties, and uses. Oils may be animal, vegetable, or petrochemical in origin, and may be volatile or non-volatile. They are used for food, fuel, lubrication, and the manufacture of paints, plastics, and other materials. Specially prepared oils are used in some religious ceremonies as purifying agents.
Wikipedia about car usage costs
The costs of car usage, which may include the cost of: acquiring the vehicle, repairs and auto maintenance, fuel, depreciation, driving time, parking fees, taxes, and insurance, are weighed against the cost of the alternatives, and the value of the benefits ? perceived and real ? of vehicle usage. The benefits may include on-demand transportation, mobility, independence and convenience. During the 1920s, cars had another benefit: "couples finally had a way to head off on unchaperoned dates, plus they had a private space to snuggle up close at the end of the night."
Similarly the costs to society of encompassing car use, which may include those of: maintaining roads, land use, air pollution, road congestion, public health, health care, and of disposing of the vehicle at the end of its life, can be balanced against the value of the benefits to society that car use generates. The societal benefits may include: economy benefits, such as job and wealth creation, of car production and maintenance, transportation provision, society wellbeing derived from leisure and travel opportunities, and revenue generation from the tax opportunities. The ability for humans to move flexibly from place to place has far-reaching implications for the nature of societies.
Overview of the car in auto-service
Every driver knows that the smooth functioning of the car are not enough working brakes and good tires, but also good oils for automobiles, especially motor oil, which helps to keep the engine in good condition. In summer, a good motor oil can protect the motor from overheating, while in winter from excessive cooling down and also prevents the formation of rust. As a result, prolongs engine life. Therefore, the review carried out in the service automotive service technicians examine whether their client's car is good enough engine oil. They can also advise the driver to select the best oil and replace the oil in his car for the better.