What is the consensus on mixing Dexos Oils? I have a full quart of 0W-40 X3 and am preparing for my next oil change.

I could buy a 6 pack of X3 for $55, but I would be short a half quart. I considered not changing the filter since I've only put on 1000 miles or so since my last oil change. Unfortunately the owners manual says you should change oil and filter at the proper interval. If I buy two 6 packs of X3 so that I have enough to change the filter and add 7-1/2 quarts of oil, that would leave me with 5-1/2 quarts for my next oil change. I am concerned that X3 will not be available a year from now and I will have $55 worth of oil that I can't use.

Sooner or later I am going to have leftover X3 oil unless I bite the bullet and
1) mix a quart of X3 with 6-1/2 quarts of DexosR or
2) just say the hell with it and not change the filter and add 6 quarts of DexosR and 1 quart of X3 or
3) change the filter and add 7 quarts of DexosR and 1/2 quart of X3

I know I can't be the first to have this problem. I am leaning towards option 2. What do you think? I miss the days when all we had to do was match the oil weight and API ratings. All this Dexos crap is for the birds. I can't believe mixing X3 and DexosR would hurt anything, but I 'm sure some of our oil experts will disagree.

Mobil 1 even says DexosR is backwards compatible with Dexos 1,2,and 3 and says that you can substitute DexosR during your next oil change, but does not say anything about mixing them. There will definitely be some oil left if you switch from one Dexos type to another so you will in effect be mixing them. Plus Mobil 1 doen't know that you will be changing hte filter every oil change so they should assume there is at least a 1/2 remaining before adding he DexosR. HHHHHHHHEEEEEEELLLLLLLLLLLLLLPPPPPPPPPP!

 

My opinion you’re over thinking it. Do it.

 

X3 meets Dexos 2
https://www.gmdexos.com/brands/dexos2/index.html

 

Why are you changing the oil? I gather that since its only been 1000 miles since the last change, you are changing it because of the 1 year requirement? The requirement is the "engine oil and filter must be changed at least once a year." So, if you are trying to comply with the maintenance requirements, you should change the filter, not just the oil.

As for the oil, your 2022 model can use dexos 2 (as you know) and Mobil 1 ESP x3 0W-40 is dexos 2 licensed.

Does Mobil really say the oils are "backward compatible"? I think its actually a statement on the gmdexos site (which is gm and pertains to the specs, not a Mobil product), and what it says is "GM dexos R engine oils meet or exceed the performance of GM dexos 2 and GM dexos 1 Gen 2 and Gen 3 oils and are backward compatible, therefore vehicles equipped with gasoline engines that used GM dexos 2, or GM dexos 1 Gen 2 or Gen 3 may use a GM dexos R licensed engine oil of the appropriate viscosity grade at their next oil change." I'm not sure the intent is that they can be mixed - after all - dexos is a specification and not a specific product. Its intent is just to tell us that cars that called for dexos 2 can now use dexos R at the next oil change.

Personally, I would just get some dexos R motor oil (there are now several, all Mobil 1 products, listed on the gmdexos site) and change the oil and filter. While I would not mix it with Mobil 1 ESP x3, I really doubt there is any issue with mixing them. Mobil 1 ESP x4 is now listed as meeting dexos R too.

So, what I would do is change the oil and the filter and use all dexos R rated oil (I would select Mobil 1 Supercar 0W-4).
But I think its probably ok to put 1 quart of the Mobil 1 ESP x3 and the rest dexos R.
What I would not do is change the oil and not the filter.

 

I wouldn't worry about mixing dexos oils. I believe the SAE specification requires any oils certified to the same SAE specification to be compatible with each other. But I'd change the filter just to be in compliance with the GM requirement if you are changing the oil because it has timed out.

 

Maybe bite a different bullet and don't buy six-packs, just buy as many quarts as you need?

 

Well, it's still not far off from that. You aren't mixing weights, you are using oil that meets the Dexos requirement. BTW, in all changes I did on my 2020 SR, it always took 8 full quarts to be at the full mark of the dipstick. If it were me, I would just put the one quart of X3 on the shelf and forget about it, and buy 8 quarts of Supercar and be done with it. It's a quart of oil, just don't buy one hamburger out and you've made up the money.

 

Or multiples. When I got mine a couple years ago Auto Zone had a super deal on oil and filter and I got enough DEXOS2 for, I think 3 years of changes.

 

Mix 'em. People have been mixing different brands and weights of oil since cars were invented. As long as they're both Dexos 2 or Dexos R, you're still meeting GM's requirements (Mobil stated, in writing, that 0W40 Supercar Dexos R was identical to the 0W-40 ESP Dexos 2, and was just a rebranding, not a reformulation.)