mtaxman

I received a ad from my selling dealer with service deals.
One of the deals was for an AC Delco Dexos synthetic oil change.

When I got my 500 mile change I made sure to ask for 9 qts of Mobil 1 and the tenth quart to do at home.

It seems like you really need to be careful - or doesn't it matter at all?
Who makes the AC Delco oil?

And the new fill viscosity is what? 0W 40?

bearphoto

While I prefer having the mobil 1 in my corvettes I suppose there is nothing wrong with the dexos as gm has approved it.

thill444

Dexos is a standard. As long as the oil meets that standard, Mobil 1 does, and the AC Delco sounds like it does, it is approved for your car. I doubt there is any difference.

LightningBolt

Just make sure you get the correct viscosity.

Patman

That is the new factory fill starting with the 2019s (and is backwards compatible for all C7s) but I think it will be difficult to find this new oil for a while, I highly doubt any dealer has it in stock yet. It's not the same 0w40 that Mobil 1 currently has, it's a new version that meets the dexos specification.

dvilin

Makes no difference at all, not sure why people think Mobil is a must have.

Squeaky Wheel

consolidated

Be interesting to see the differences between M1 0w-40 Euro (fill for BMW, M-B & Porsche) as it’s currently available on the shelf versus GM’s Dexos certified M1. Maybe it’s got more ‘merica in it.

xp800

FWIW, the 2 or 3 (w/dry sump) free GM Complete Care oil changes that come with the Corvette for the first 2 years are specified by GM to use Mobil 1 and have been for some time. There are memos and service bulletins on this. Many dealers still don't understand this and are simply ignorant of the published guidelines on the matter.

However, the current OEM GM bulk and quart dexos1 certified 5w-30 are now fully synthetic vs. semi-syn that it had been previously. This happened in 2015 somewhat silently as part of the gen 2 dexos1 spec update. And I'd wager that it's made by Mobil as it's been in the past. And I'd wager it's 95% the "same" as actual Mobil 1. And to that end, for 99% of Corvette owners, this means it's far more than good enough for street use. That said, I'm a bit of an oil snob and prefer Penzoil synthetic over M1 if I'm paying, but I would have -zero- issues using the OEM GM dexos1 oil now that it's fully synthetic and "free" with a new car maintenance program.

The past few times I've taken my other GM vehicles in for the free oil changes in the past 1.5 years, all the service advisors have commented that the GM oil is now synthetic. Originally (in early 2016) I was confused because they said it in the context of "your car requires synthetic oil" thinking they wanted to upcharge me. I originally replied "No, it just requires dexos1 certified oil". Then I had to eat a bit of humble pie when the advisor mentioned the spec update and the shift of AC Delco oils to fully synthetic for dexos1 applications. Remember, us Corvette folks are supposed to know more then the advisors, right? Well, I got smarter that day.

Some background -DATA-:

http://www.centerforqa.com/dexos-brand2015/ (notice all the GM North America oils are synthetic)

Additionally:

The only OEM engine oils GM shows on their ACDelco north America site...

http://www.acdelco.com/auto-parts/ve...ubricants.html

Are fully synthetic:

http://www.acdelco.com/auto-parts/ve...il-dexos1.html

4thC4at60

Could run dino oil if you wanted, just might want to change it at 3,000, rather than around 5,000....

When was the last time you heard of any engine failing due to oil failure?

Oil pump, sure. Oil itself.... er, no........ unless you're too stupid to change it, then, that's on you.

red62vette

BTW AC Delco doesn't make their own oil. It is likely made by Mobil, Castrol, or Pennzoil. I know the BMW branded oil is made by Castrol.

JerryU

GM is not in the oil business! My guess is whatever they have that dealers can buy may be at any time by the one who gave them the best price!

Look at the list of ~100 brands GM lists as meeting dexos spec. Some are blends! If you're happy with a blend-fine.

Dealers are independent businessmen. They must use dexos approved oil but it could be Oh-So-Peachy brand that is on the GM approved list (and who paid them a tribute to have it listed) and who gave the dealer the best price. There are names on that list I never heard of! Why not as 99+% of the cars/trucks they service only need it to be dexos approved.

As I have been, I will buy dexos approved 5-30 Mobile 1 at Walmart for $22/5 gallon jug and get my $12 Mobil rebate per jug paying about $2/quart. If the European 0W 40 Walmart has in stock for the same price as 5-30 is dexos approved I might use that! It may not be as it is listed for BMW, Porsche, Mercedes and Audi who could care less if Mobil pays GM a tribute to have the listing!

PS: I have been using Mobil 1 since 1974 when the Datsun service manager recommended it to solve a unique problem. I then used it in my Modified Corvair where the oil got to 300 F when I was driving aggressively!

However it all changed in ~2000 when Miobil sued Castrol for labeling a more highly refined "dino" oil as synthetic-and lost. As this fun article says, it cost half of the prior "real synthetic I had been using! https://www.caranddriver.com/columns...mantics-column

The author equates the word synthetic after Mobil lost, to Bill Clinton's famous statement, "Depends on what the meaning of 'is' is!" Because of cost all companies switched to this cheaper product. The price did drop!

TEXHAWK0

I use Valvoline synpower in all my cars, including the Stingray. As pointed out Mobil 1 us not what it used to be, and there are other "synthetic" oils that are equal or better.