Do not add anything to the oil. The recommended oils meeting the dexos specification are all that is needed for good performance and engine protection.
Engine oil system flushes are not recommended and could cause engine damage not covered by the vehicle warranty.
Selecting the Right Engine Oil
(Diesel Engines)
What to Do with Used OilRail Replacement - Rear Section
Removal ProcedureWarning:Refer toApproved Equipment for Collision Repair Warning.Disable the supplemental inflatable restraint (SIR) system.Refer toSIR Disabling and Enabling.Disconnect the negative battery cable. Refer toBattery Negative Cable Disconnection and Connection.Remove all related panels ...