Multi Grade 4 stroke motor oil 10W-30, SE,SF,SG,SH = Brand name, equivalents ?

These letters certify that the oil has been tested and meets the standards set by the API (American Petroleum Institute). All brands use the same service rating method, Higher letters mean better performance of the oil. You can use a higher letter than recommended, but unless you find some old stock somewhere, any name brand oil you buy will meet the latest specifications. The current standard is SM, so I doubt if you'll find any of the SE-SH rated oil you asked about. The API considers any oil with a rating of lower than SJ to be obsolete and not suitable for use in today's autos. The rating is always on the label. http://api-ep.api.org/filelibrary/API_Mo鈥?/a>