@SubieRubyRoo that’s an excellent question. Based on my knowledge, it would likely be challenging to formulate an oil that meets dexos requirements without also meeting API specifications. All the additive packages I’ve encountered that comply with dexos standards have also met an API specification with the same treat rate. The only scenario in which this might occur is if GM permits the use of a base oil, co-additive, or viscosity index improver (VII) that is not explicitly approved by the API.
