Dexos-approved engine oil is engine oil carrying the Dexos specification created by General Motors designed to inform customers that the oil meets GM specifications. Oil manufacturers must pay to obtain the Dexos license in order to display the Dexos logo.
Dexos-approved oils are typically fully synthetic or synthetic blend oils designed to increase fuel mileage and length between oil changes. Gasoline-powered vehicles use Dexos1 oils while diesel-powered vehicles use Dexos2 oils. Vehicle owner's manuals commonly suggest using manufacturer specified engine oils to avoid voiding the vehicle's warranty. However, Valvoline said these claims are false provided the owner uses an alternate oil of comparable quality.