The kind of motor oil used to lubricate the moving parts of a car's engine depends on a number of factors. These include the age of the vehicle, the climate the car is driven in and how much a consumer is willing to spend.
The older the automobile, the thicker the viscosity of the oil needed. Mechanical parts wear down over time and require a thicker, more readily coating oil to preserve moving components. Additionally, colder climates naturally thickens oil, while warmer climates thin it out. An oil that is too thin, either by composition or temperature, won't effectively lubricate engine parts. Finally, there are three overall types of oil: natural, synthetic and synthetic blend. Natural oil contains the greatest amount of impurities that will contaminate an engine over time, but tends to be the cheapest of the three types. Synthetic oil generally costs up to three times as much as natural oil, but contains significantly fewer impurities and lasts longer. Blend is a mixture of natural and synthetic oils, and it is usually cheaper than pure synthetic.