What To Look For When You Choose Your Oil
When it comes to oil for your vehicle, there's no one-size-fits-all solution. It's important to understand all the symbols and acronyms on product labels to ensure you're choosing the optimal oil for your specific needs.
API's Certification Mark & Service Symbol
This identifies quality motor oils for gasoline and diesel-powered vehicles. Oils displaying these marks meet performance requirements set by U.S. and international vehicle and engine manufacturers and the lubricant industry.
The American Petroleum Institute's "Starburst" means that the oil meets the gold standard of ILSAC, the International Lubricant Specification Advisory Committee. ILSAC establishes quality specs for the world's lubricant standards - a joint effort of U.S. and Japanese automobile manufacturers.
The API "Donut" seal provides performance levels, viscosity grade, and savings from fuel conservation. It is typically shown on the back of the oil container.
Resource Conserving & Energy Conserving: These designations apply to oil intended for gasoline cars, vans, and light trucks. Widespread use of "Energy or Resource Conserving" oils may result in an overall savings of fuel in the vehicle as a whole.
Performance Level: Motor oils designed for cars, vans, and light trucks with API's "S" (Service) categories. Motor oils designed for heavy-duty trucks and vehicles with diesel engines fall under API's "C" (Commercial) categories.
Viscosity Grade: Viscosity is a measure of an oil's flow characteristics, or thickness at certain temperatures. The temperature requirements set for oil by the Society of Automotive Engineers (SAE) is 0 degrees F (low) and 210 degrees F (high). On an oil container, the low temperature viscosity (e.g. 5W) indicates how quickly an engine will crank in winter and how well the oil will flow to lubricate critical engine parts at low temperatures. The higher temperature viscosity (e.g. 30) provides thickness, or body, for good lubrication at operating or higher temperatures.
Multiple Performance Levels: Oils designed for diesel engine service might also meet gasoline service. For these oils the designation is "C" category first, followed b the "S" category. "C" category oils have been formulated primarily for diesel engines.
CK-4 Designation: Engine manufacturers are expected to recommend API CK-4 oils for on-highway and non-road diesel engines in use today in heavy-duty equipment. CK-4 oils have improved oxidation resistance, shear stability, and aeration control compared with CJ-4 products. CK-4 oils are backward compatible with CJ-4, CI-4, CI-4 PLUS, and CH-4 oils. Still, you should check with the engine manufacturer before moving up to CK-4. Remember to ask about your oil change interval when using CK-4.