School me on what Dexos really is

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Hello to all,

I haven't been on this forum for some time and need some old time schooling.
I just had an oil change done on my 2013 Camaro and wanted Mobil 1. When I got it back home I noticed they use Dexos brand of oil.
Are or Is Dexos the same as M1?

Durango
 
It is GM's oil specification. Just like Dexron for transmissions and Dexcool for coolant. I don't think I have ever seen a set of exact specs, but it is supposed to be better than basic API SN/ ILSAC GF-5. Several major name brands and even several house brands are Dexos.
 
Dexos is a spec for oils that GM created. I believe that it came around in 2011 or 2012. It has minimum standards for various aspects of the oil's performance (i.e. shear stability, deposit formation, etc.)
Most off-the-shelf synthetic oils (PP, M1, VSP etc) meet Dexos, as well as Supertech and other store brands.
Synthetic blends can also meet Dexos, though they are generally robust blends with a high percentage of synthetic in them.

"Synthetic blends" that are really just conventional with a splash of synthetic to meet SN (i.e. many conventionals- VWB, Chevron Supreme, etc.) do not meet Dexos. Some of the higher-percentage blends do though. But your PYB, Formula Shell, Havoline, QSGB, VWB, etc. do not meet the specs.
(There is now Dexos Gen 2, a revised spec that is more exclusive and harder to pass. It rolled out recently.)
 
Very good post TmanP.

Durango if your service was at a GM dealership I would think you got Conoco Phillips Dexos approved oil. Though it also could have been the older GM Dexos oil provider of Exxon Mobil I think. Either would be very good for your Camaro.
 
Originally Posted By: AZjeff
So nobody knows what the Dexos specs are?


The info should be on the internet somewhere. The spec is not a proprietary one; you can submit for licensing.
 
Dexos1 Gen1 was a licensing program that certifies that oil is of good quality - most synthetics and many blends meet this requirement. Now, Dexos1 Gen2 is a little stricter and was specifically designed to combat LSPI (low-speed pre-ignition) which is important For small displacement turbo-charged direct injection engines...
 
Originally Posted By: Durango
School me on what Dexos really is


Grounds to deny warranty coverage.


Sorry couldn't resist. Carry on.
 
GM Dexos Motor Oil Specifications

GM Dexos approved oils are recommended to be used in all GM vehicles except those built with Duramax diesel engines that require an API CJ-4 quality oil.

GM Dexos 1
Designed with gasoline engines in mind GM Dexos 1 replaces the GM-LL-A-025, GM6094M and GM4718M specifications. This specification is usually recommended for GM vehicles built for the North American and Asian markets. Compared to ILSAC GF-5 it has stricter requirements regarding piston deposit formation, aeration, oxidation stability, wear, low-temperature pumpability and volatility.
GM Dexos 2
The GM Dexos 2 specification is meant to be the replacement for both GM-LL-A-025 (gasoline) and GM-LL-B-025 (diesel) specifications for the European market. Oils meeting GM Dexos 2 are required for vehicles manufactured from MY2011 onward but they are also backward compatible with older models. This specification is built on the ACEA C3 standard but also contains elements from the ILSAC GF-4 deposit formation test and low-temperature sludge build-up test.
 
Thanks Warstud. Pretty generic. Is it possible to find the details for the other GM oil specs listed or are they all top secret? Tried searching and didn't see any solid numerical specifications. Just curious.
 
Good job Warstud.

AZJeff I know that the NOACK volatility needs to be less than 13% for Dexos approval. Versus API SN of 15%. The latest configuration of Dexos approval is about LSPI, timing chain wear standard as well.

I saw the specific numbers somewhere but I forget where I saw them.... Will try to see if I can find them.
 
Last edited:
Originally Posted By: Warstud
GM Dexos 2
The GM Dexos 2 specification is meant to be the replacement for both GM-LL-A-025 (gasoline) and GM-LL-B-025 (diesel) specifications for the European market. Oils meeting GM Dexos 2 are required for vehicles manufactured from MY2011 onward but they are also backward compatible with older models. This specification is built on the ACEA C3 standard but also contains elements from the ILSAC GF-4 deposit formation test and low-temperature sludge build-up test.

Would a Dexos 2 relatively surpassed an ACEA C3 in:
a)Higher percentage good base oils;
b)Higher base oil quality ;
c)Higher amount and higher quality additives ?
TIA
 
Originally Posted By: AZjeff
So nobody knows what the Dexos specs are?

http://www.aftonchemical.com/Afton/media/PdfFiles/Specification_Handbook.pdf starting on page 110.
That pdf file is still on dexos1 Gen1, so if you want dexos1 Gen2, you can add tests for Low Speed Preignition and Timing Chain Wear. Also the GM Oxidation Test.
You can see from the pdf file there are a bunch of tests added over and above SN GF-5. Bottom Line: better oil, for GM, Ford, Japanese, Korean cars and trucks, not just GM vehicles.

Its probably very close to LL-01FE and LL-14FE BMW requirements these days, a couple of low-ish HTHS oil specs that are very respected.
In fact I've told people, the best 0w20 or 0w30 might just be the BMW-Mini branded oils that meet those specs, but dexos1 Gen2 is right in there too.
 
Its likely a convenient revenue stream for GM through ongoing licensing fees, the fact that they assure a certain quality of oil in their leases is just a bonus.
 
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