[Evergreen6]

Originally Posted by Dynamical

How long before we see some of the Dexos 2 oils magically change to Dexos R over night? That's what happened with the Mobil One esp 0w40 after GM waved its magic wand. That owners manual SS posted speaks of a 5w30 dexos R which does not exist....YET. Only Dexos R available is 0w40 and 5w50 supercar.

Unless I'm reading it wrong, I think the 5w30 DexosR is a typo in the owner's manual. In the first red box, it says 5w30 Dexos1 can be used instead of 0w40.

[haggler]

This is also interesting:
Please note: GM dexos 2 is being discontinued in 2025 and replaced by GM dexos D and GM dexos R. Vehicles equipped with diesel engines that used GM dexos 2 engine oil will use GM dexos D licensed engine oils, while vehicles equipped with gasoline engines will use GM dexos R licensed engine oils of the of the appropriate viscosity grade at their next oil change.

so the Dexos2 oil license for gas engines will convert to DexosR. This further lends credibility to the fact that DexosR is basically rebadged Dexos2. Sleep easy with the Autozone deal...

[Evergreen6]

That makes some sense, at least. GM's little diesels do/did require Dexos 2, but the Dexos 1 icon actually looks like a number 2, so unless you know exactly what you're looking for, it can be easily confused. And then they came out with Dexos D for diesels, but Dexos 2 was still specified for the little diesels, but apparently is also used in gas engines as well. Oh, hell.

Dexos 1 then went generation 2, and generation 3, meanwhile Dexos 2 (Generation 1?) was still required for Diesels, or maybe a gas car requiring the correct ACEA designation. Confused yet?

Now there's Dexos R which I understood to supersede D1/2 for high performance engines but apparently it's really just Dexos2. Licensing this stuff for bottles has got to be a mess. I wonder if everyone now has to re-license under Dexos R.

[ember1205]

Originally Posted by GearheadSS

The Owners Manual is your best friend.

While generally great info, I just want to point out that this is an instance of GM being completely borked with information. They tell you that 5W-30 dexosR is fine for street use. But, there IS NO SUCH OIL.

[SuperSnake1972]

Has anyone tried ULTRA1 full synthetic 5W40 ?