I need an oil change and I cant find an oil that has SG in the label. What should I use?

You can use oil with an API rating of at least SG and therefore can use today's oils with an SN rating. The API service rating is basically a classification assigned to signify the oil's ability to reduce friction and oil consumption, improve emissions, and provide better lubrication. The API ratings are backwards compatible, but not vice versa, meaning SN will work for SG but SJ will not work for SM.

The current API index for engine oil is SN this oil meets or exceeds the SG oil grade you are looking for. These ratings change over the years so when your car was made the rating was SG then it went to SH then to SJ and so on.
The latest API service standard designation is SN for gasoline automobile and light-truck engines. The SN standard refers to a group of laboratory and engine tests, including the latest series for control of high-temperature deposits. Current API service categories include SN,SM, SL and SJ for gasoline engines. All previous service designations are obsolete, although motorcycle oils commonly still use the SF/SG standard.

The letters stand for how the oil is rated. the "S" means for spark ignition engines "C" is for compression ignition engines (Diesels). The second letter is the "grade". So any letter that is AFTER "G" is good to use. Like "H" OR "J".. Hope this helps and now you know what the letters on the oil container stand for.