Standard Engine Oil Ratings/Grades

[Joemm]

With all the discussion and often confusion regarding oil, I thought the following would help.

http://www.apicj-4.org/EngineOilGuide2006.pdf

http://www.apicj-4.org/engineoilguide2006.pdf

The bottom line on an oil's vehicle applicability and engine protection ability boils down to the American Petroluem Institute (API) rating, SM is the currently the highest rating, and Society of Automotive Engineers (SAE) viscosity rating, e.g., 5w-30.

Unfortunately, the oil name, color, or brand really does not mean much if the API and SAE ratings are the same, e.g., API-SM, SAE 5w-30 oils all provide the same minimum level of protection and longevity between changes.

With that said, some manufactureres may include additives another might not which may or may not add some (claimed?) benefit, e.g., enhanced sludge protection. However, if your goal is to protect your engine to or above OEM warranty specs and keep it running like new for years/miles, look for the API and SAI ratings and less at the brand name and you'll likely save yourself a good amount of advertising dollars.