Originally Posted By: GM
Further, GM says that if a customer has an engine failure that is traced to oil or lubrication issues, and if the customer does not use dexos 1 oil in their gasoline-powered GM vehicle, that act alone could void the warranty.
This doesn't mean "use it or void your warranty...". You can still use non approved, Castrol, Valvoline, Amsoil recommended oil that meets dexos. Warranty is voided if it is determined that the oil used caused the engine failure.
Originally Posted By: Castrol
When asked: If a dexos1™ license engine oil is not used in an engine that calls for dexos1™, will the warranty be voided?," Castrol says, "No." They continue by adding, "In order for the warranty to be voided, the engine manufacturer must prove that the engine oil caused the failure. If the engine oil meets / exceeds the requirements of dexos™ 1, the warranty can not be voided just because the engine oil in question is not officially licensed."