The Short Story
For most, here's all you need to know: Buy a brand name oil that exactly matches your vehicle manufacturer's specifications and certification requirements, and change your oil according to the carmaker's recommendations. That will allow your engine to offer maximum performance and last as long as possible. Disastrous consequences await those who deviate from the manufacturer's recommendations.
Weight and Oil Viscosity
Oil is like pancake syrup. Without blending and additives, on cool days oil would be as thick (viscous) as Mrs. Butterworth's stored in the refrigerator. At high temperature, though, it would get uselessly thin, like microwaved syrup. Long ago, the Society of Automotive Engineers developed a rating system for oil viscosity, the most basic of characteristics, which is often called weight. It's expressed by four or five characters, such as 10W 30. The lower the number before the W (for "winter"), the better it flows in cold temperatures. The number after the dash indicates how well the oil flows when it's warm. Higher numbers mean the oil is "heavier," or more viscous. Multi-viscosity oils developed several decades ago mean you don't have to worry about using different oil for winter and summer.
Don't select heavier than recommended oil in the mistaken belief it'll provide better protection. Old-timers are used to heavier oils, but many manufacturers currently specify light oil, such as 5W-20. One reason is that some modern engines have incredibly tight clearances between parts. Especially when the engine is cold a heavier oil may not reach into these tight-areas. The lighter oil also helps provide better fuel economy.
Certifications
Quality oils carry up to three certifications from three different organizations. Your owner's manual will say which standard is required. These certifications indicate that the oil met the testing and content requirements of these organizations. The most well known is the American Petroleum Institute's (API) "starburst" and "donut." In the center of the API circle is the SAE weight . The outer ring will say "API SERVICE" followed by two letters: "SM" has been the top API rating since 2004, and API says it'll work in all automotive gasoline engines. If the service rating starts with a "C," it's for diesel engines.
American and Japanese automakers combined to create the International Lubricant Standardization and Approval Committee . Its current standard is GF-4. A new standard, GF-5, is scheduled for 2010. Finally, some European cars require oil certified by the European Automobile Manufacturers' Association.
Why Oil Additives?
Without a myriad of additives, motor oil could not meet the demands of modern engines. Detergents in oil trap impurities. Polymers increase high-temperature performance. Molybdenum is now used instead of sulfur to decrease wear at high-friction points. Oil designed for high-mileage engines has seal conditioners to reduce oil leaks. And these are but a few of the engine oil additives.
www.usedenginenexus.com
