Can anyone tell me the GM code required for oil in your C6?

[Ruby Fan]

I own a C4 and the GM code required for synthetic oil is 'GM4718M'. Is this still the code required for syn oil on your new C6 cars? Was it changed or an additional code added? I see the word 'performance' added to some synthetic oil products. thanks

 

[catbert]

GM has changed the recommended or required spec many times lately. The technology is evolving constantly. The current GM standards are Dexos and GF-5. The constant updating of specs allows, among other things, extended oil change intervals of up to 10 thousand miles, under the right driving conditions.

It would be logical that you are probably OK using the latest spec oil on older models. The older rating system is a product of the American Petroleum, and uses the starburst logo. The newer system is the brainchild of the manufacturers and some of the oil formulators.

Google is your friend. There is lots of information out there

 

[Hib Halverson]

Actually, "Dexos" is a brand name trademarked by GM. It becomes a specification when followed by the appropriate number.
"Dexos 1" describes engine oil that's generally for gasoline engines. It replaces previous GM specs: GM-LL-A-025, GM6094M and GM4718M.
"Dexos 2" describes engine oil that's generally for light-duty diesel engines. It replaces previous GM specs: GM-LL-B-025 and GM-LL-A-025

GF5 is neither an API nor a GM specification, it's an ILSAC rating.

For 92-up C4 LT1/LT4 and 93-up C4 ZR-1 the minimum spec the oil must meet is GM4718M.

With Corvette GM no longer specifies oil drain intervals by mileage...hasn't done that in a long time. Change the oil when the "change oil" oil light or once a year. Some like to change the filter at 50% oil life.