ACDelco GM Original Equipment Motor Oils are designed, engineered, and tested to rigorous standards, and are backed by General Motors. Dexos oil is the latest low viscosity diesel engine oil specification from GM. It is designed to meet the enhanced performance needs of today's GM vehicles. Unlicensed products have not gone through GM's rigorous testing process, are not monitored for quality, and are not approved or recommended for use in GM vehicles. ACDelco GM Original Equipment parts are the true OE parts installed during the production of or validated by General Motors for GM vehicles. Some ACDelco GM Original Equipment parts may have formerly appeared as GM Genuine Parts (OE) or ACDelco Professional.