The difference between 5w-20 and 5w-30 oil is that 5w-30 oil has a higher viscosity at its operating temperature. Viscosity is the term used to describe the thickness of a substance, in this case oil, where a higher number indicates a thicker oil.Know More
Oil viscosity varies inversely with temperature. This means that as the temperature goes up, the thickness (viscosity) of the oil decreases. To use this knowledge in an automotive application, it is important for an oil to be thin enough to spread quickly when a cold engine is started, yet it should not become too thin once the engine reaches its operating temperature. An oil with the rating of 5w-30 is a multiweight oil that will act like a 5-weight oil, which is very thin at cold temperatures, while maintaining the thickness of a 30-weight oil once the engine reaches its operating temperature. This protects the engine from wear at both temperature extremes.
The invention of the modern multiweight oil is made possible by the addition of polymers, which coil up at cold temperatures and mimic shorter molecular chains with a lower viscosity. As the oil's temperature rises, these polymer chains begin to unwind, increasing the effective length of the molecular chain and thereby increasing the viscosity.Learn more about Engine Oil
The two oil types differ in their high temperature viscosity, and 10w40 is thicker than 10w30 when it comes to high temperatures. Before multi-grade oils were formulated, car owners typically used 10w30 for its wintertime flow properties, while relying on the 10w40 for the summertime when temperatures warmed up.Full Answer >
Synthetic oil may last anywhere from 5,000 to 7,000 miles before it needs to be changed, although some brands may last as long as 10,000, 15,000 or even 20,000 miles. Change interval length also depends on factors such as road conditions and trip mileage.Full Answer >
Synthetic oil is generally better than conventional oil or blends because it lasts longer and may improve the car's performance. However, it is also usually significantly more expensive.Full Answer >
Dexos oil is motor oil that is licensed by General Motors to carry the dexos specification. The dexos specification is awarded to oils that have passed a number of tests conducted by GM and that have paid for the dexos license.Full Answer >