GM Dexos1 Gen 2 vs. Gen 3 spec

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This article is well-written and covers many of the major differences.

I thought this point was interesting:

Are Group II+ base oils allowed in dexos1 Gen 3 formulations?

Group II and II+ base oils are certainly allowed in dexos1 Gen 3 formulations, but GM will allow limited to no read-across for formulations that contain greater than 30 percent group II/II+. This typically applies to 5W formulations and could possibly apply to 0W formulations with a GIII+ or PAO trim fluid.

This leads me to believe that some of the house-brand Dexos approved oils right now are probably using II/II+ to some degree.

I have a feeling that the flagship full synthetic oils from the major brands (M1, PP, Edge, Valvoline) are probably capable of meeting the spec after the SP reformulation, but the generic oils may need to be revisited.
 
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I see that there is a. mandatory transition to gen 3 by 9/1/22. Is there a rollout phase where producers will release gen 3 before that date? If so, when.
 

The Critic

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Sounds like GF-6, Dexos 1 Gen. 1 & 2 must cause dirty turbos? Zero to perfect cleanliness with D1G3!
Right?

I think this goes to show that oils are barely keeping up with demands of the latest engine designs. Some of the engines being used in the Gen 3 tests have already been in use for several years.
 
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The turbo thing is interesting. Almost as if they missed it the first two go-rounds. Its not like they didn't test on turbo engines, that's where the whole LSPI thing came from.

Certainly will have me looking for it for the 2.3L, the Honda's still won't care :)
 

SR5

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I was looking at the lubrizol relative performance tool for Dexos1-Gen2 Vs Dexos1-Gen3.

They are the same for after treatment compatibility and for fuel economy and for sludge control.

The D1-G3 show a small improvement for oxidative thickening and for deposit control.

However for Wear, the older D1-G2 is better by a large amount and it seems D1-G3 has gone backwards here. Have a look for yourself


Is this a mistake in the chart ? I would assume they would at least stay the same as the standard progresses.

BTW for Sulphated Ash (SA) D1-G2 is <= 1.0% while D1-G3 has been reduced to <= 0.9% which doesn’t surprise me as most oils are going to lower SAPS levels as the fuel quality improves (less sulphur).
 
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I was looking at the lubrizol relative performance tool for Dexos1-Gen2 Vs Dexos1-Gen3.

They are the same for after treatment compatibility and for fuel economy and for sludge control.

The D1-G3 show a small improvement for oxidative thickening and for deposit control.

However for Wear, the older D1-G2 is better by a large amount and it seems D1-G3 has gone backwards here. Have a look for yourself


Is this a mistake in the chart ? I would assume they would at least stay the same as the standard progresses.

BTW for Sulphated Ash (SA) D1-G2 is <= 1.0% while D1-G3 has been reduced to <= 0.9% which doesn’t surprise me as most oils are going to lower SAPS levels as the fuel quality improves (less sulphur).

dexos1%20Gen3%20spider%20chart%20June%202021.jpg
 
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I was looking at the lubrizol relative performance tool for Dexos1-Gen2 Vs Dexos1-Gen3.

They are the same for after treatment compatibility and for fuel economy and for sludge control.

The D1-G3 show a small improvement for oxidative thickening and for deposit control.

However for Wear, the older D1-G2 is better by a large amount and it seems D1-G3 has gone backwards here. Have a look for yourself


Is this a mistake in the chart ? I would assume they would at least stay the same as the standard progresses.

BTW for Sulphated Ash (SA) D1-G2 is <= 1.0% while D1-G3 has been reduced to <= 0.9% which doesn’t surprise me as most oils are going to lower SAPS levels as the fuel quality improves (less sulphur).
Lubrizol specifically addressed the wear test:

NOTE: the relative performance of the dexos® 1 Gen 3 wear specification is ranked slightly lower than dexos® 1 Gen 2 since GM removed an engine test (RNT) and replaced it with a bench test (MTM). Generally, an engine test is a better method of evaluating performance. The specification does still utilize the Sequence IVB wear test, which is also part of the API and ILSAC specifications. The sludge-handling performance comparison is a similar situation where GM removed a sludge handling engine test (M271 EVO) and replaced it with the Sequence VH (API/ILSAC), a final formulation test with more stringent limits than those of ILSAC GF-6.

The specification ensures that all dexos® 1 Gen 3 oils will still be very strong on wear protection and sludge handling and reflects the emphasis that has been put on cleanliness, fuel economy and LSPI protection for GM vehicles.
 

SR5

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In a recent thread I asked the oil formulator @weasley a question

Q) Talking specs, how close is a new API SP & ILSAC GF-6 oil to a Dexos1-Gen2 oil? Assuming the same viscosity grade.

A) It's a tricky one to compare - the dexos specs use a mix of API-type and ACEA-type engine tests, as well as a fair few GM-specific tests. For the engine tests that are common to API/ILSAC and dexos1g2, the dexos spec is slightly tougher in the Sequence VG (sludge and varnish) and matches SP for fuel economy (ILSAC demands better FE). All other common tests are equal in demands.


Comment from SR5, that Oronite spider chart (posted by tyman above, and linked to by the OP) doesn’t show the higher fuel economy demands of GF-6 over D1-G2. Also the Lubrizol chart shows no significant change in FE from D1-G2 to D1-G3, yet the Oronite chart does show a change.
 
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The turbo thing is interesting. Almost as if they missed it the first two go-rounds. Its not like they didn't test on turbo engines, that's where the whole LSPI thing came from.

Certainly will have me looking for it for the 2.3L, the Honda's still won't care :)
Did they not test, or was there no parameter for performance set by the spec?
 
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