Please help me understand

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Sierra048

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Courtesy of Wemay, I asked this question in the wrong thread and it never went anywhere so I thought I'd ask again. Looking at the voa values, and recognizing there are no 10w30 oils with Dexos approval, my question is why not? Specifacally for the above listed Valvoline Synpower. These values seem almost identical across the board. What other factors make a 10w30 not Dexos adequate?
 
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What other factors make a 10w30 not Dexos adequate? I would imagine it's because GM doesn't specify 10w30 in any of it's vehicles.(Dexos is a GM spec) That doesn't mean that it wouldn't perform well especially in Florida, California etc....(warmer climates).
 
GM owns Dexos. No GM vehicles spec 10w-30. There is no need for oil manufacturers to pay GM for the use of Dexos on 10w-30 oils.
 
Originally Posted By: Sierra048
What other factors make a 10w30 not Dexos adequate?
Probably cold flow properties and the fuel economy aspects that it affects.
 
Not a single pour point made it to -40 which makes me think we have a lot of GRP 3 in these oils, which is fine with me, just an observation.I used to be a big fan of high VI numbers but now I’m not so sure. The 5w20 had the lowest VI of the bunch but had the the best Noack value. Doesn’t answer the question of why 10w30 isn’t Dexos rated but my wifes’ ‘98 Northstar Cadillac was spec’d for 10w30, so at some point 10w30 was ok with GM, probably before there was any serious discussion about fuel economy.
 
Originally Posted By: Reddy45
Seems like API has most of that covered,
IMO, API has historically only covered the basics, the bare minimum. As engines have become more advanced in search of improved performance, fuel economy, and longer OCIs, this brought about requirements for better performing oils. API requirements didn't go far enough, so most engine manufacturers came up with their own oil standards. GM isn't the only one that has its own oil specifications. And interestingly enough, dexos requirements encompass other engine mfg and industry specs, for example, Mercedes, Peugeot, and ACEA. All the spec requirements are in one of the tabs of this Excel: http://www.centerforqa.com/media/D1%20Candidate%20Data%20Package%20rev20170910.xls
 
Thanks for the replies. Dexos approval via payments to GM wasn't what I was curious about. It was strictly the make-up of the oil that had me wondering. I thought I read where a Dexos certified oil had to have less than 1.0 sulfated ash and a noack of 10 or less. If this is wrong please let me know. If not, the 10w30 certainly meets these criteria. Anyone know of any other specs that a 10w30 wouldn't meet? Quatro Pete: cold flow properties is noted. Is that a big factor in Dexos approval? And wouldn't a 10w30 at operating temps would perform just like a 5w30, so would fuel economy be affected that much? I'm not arguing, just asking.
 
Originally Posted By: Sierra048
Thanks for the replies. Dexos approval via payments to GM wasn't what I was curious about. It was strictly the make-up of the oil that had me wondering. I thought I read where a Dexos certified oil had to have less than 1.0 sulfated ash and a noack of 10 or less. If this is wrong please let me know. If not, the 10w30 certainly meets these criteria. Anyone know of any other specs that a 10w30 wouldn't meet? Quatro Pete: cold flow properties is noted. Is that a big factor in Dexos approval? And wouldn't a 10w30 at operating temps would perform just like a 5w30, so would fuel economy be affected that much? I'm not arguing, just asking.
Not sure about the sulphated ash but Noack limit for dexos1 is 13%.
 
Maybe it's as simple as GM decided not to certify any grades as dexos1 except 5w-30 (the only one at the outset), 0w-30, 5w-20, and 0w-20, no matter what properties they had aside from grade.
 
Originally Posted By: double vanos
Not a single pour point made it to -40 which makes me think we have a lot of GRP 3 in these oils, which is fine with me, just an observation.I used to be a big fan of high VI numbers but now I’m not so sure. The 5w20 had the lowest VI of the bunch but had the the best Noack value. Doesn’t answer the question of why 10w30 isn’t Dexos rated but my wifes’ ‘98 Northstar Cadillac was spec’d for 10w30, so at some point 10w30 was ok with GM, probably before there was any serious discussion about fuel economy.
dexos1 didn't go live until 2011, so it's quite a bit younger than your wife's Caddy.
 
I honestly think that the Valvoline 10W30 synthetic above would meet all the quality requirements of being a Dexos oil. Especially given they were probably formulated as a group and all have the same nominal values for features like sulphated ash, TBN, Zinc, etc. It's just that 10W30 is not an allowed viscosity grade under Dexos. Why? Because I assume GM want people to see the Dexos logo on a bottle of oil and know it's suitable for their GM car without having to think more about it. If it was a 10W30, it would not be suitable for very cold climates (below 0F or -20C), and the person would have to select the correct Dexos oil for their climate eg the 5W30 instead of the 10W30. I think GM is worried about people selecting the wrong oil for their car, so they made the approved Dexos grades suitable for a very wide climatic variation and the largest customer base possible. It's more about making the oil selection process as easy and as fool proof as possible for the general public, who may not find oil very interesting (I know !!). I think 10W30 is a great viscosity grade as it is naturally shear stable and with low Noack volatility, it's just not suitable for very cold climates, but a great oil in a warm climate.
 
Originally Posted By: bigj_16
Because it is a 10W-30.
+2 From what I gathered over the time being interested in oils, back in the days viscosity modifiers weren't as advanced as today and 10w-30 was a "go to" type of oil because it would not shear as quickly. Nowadays, GM isn't even considering 10w-30 in their spec as illustrated below. Technically, if 5w-30 with current viscosity modifiers stays in grade as long as 10w-30 you gain nothing by running 10w-30. On the opposite side, 5w-30 offers better flow at start up, while at the operating temperature both expected to behave the same. Also, notice low temperature cranking viscosity requirement. 10w-30 probably doesn't meet it, as someone I think had mentioned already.
 
Originally Posted By: Sierra048
Quatro Pete: cold flow properties is noted. Is that a big factor in Dexos approval?
I don't know if it's a big facfor, but it's one of the requirements, and you have to meet them all to qualify.
Quote:
And wouldn't a 10w30 at operating temps would perform just like a 5w30, so would fuel economy be affected that much? I'm not arguing, just asking.
Yes, at operating temp there should be no difference, but the fuel economy tests are performed in various conditions, including on a cold engine in cold weather.
 
Originally Posted By: Quattro Pete
Originally Posted By: Sierra048
Quatro Pete: cold flow properties is noted. Is that a big factor in Dexos approval?
I don't know if it's a big facfor, but it's one of the requirements, and you have to meet them all to qualify.
Quote:
And wouldn't a 10w30 at operating temps would perform just like a 5w30, so would fuel economy be affected that much? I'm not arguing, just asking.
Yes, at operating temp there should be no difference, but the fuel economy tests are performed in various conditions, including on a cold engine in cold weather.
Which would explain the Dexos focus on low temperature performance.
 
Originally Posted By: Quattro Pete
Originally Posted By: Reddy45
Seems like API has most of that covered,
IMO, API has historically only covered the basics, the bare minimum. As engines have become more advanced in search of improved performance, fuel economy, and longer OCIs, this brought about requirements for better performing oils. API requirements didn't go far enough, so most engine manufacturers came up with their own oil standards. GM isn't the only one that has its own oil specifications. And interestingly enough, dexos requirements encompass other engine mfg and industry specs, for example, Mercedes, Peugeot, and ACEA. All the spec requirements are in one of the tabs of this Excel: http://www.centerforqa.com/media/D1%20Candidate%20Data%20Package%20rev20170910.xls
Well, most OTS syn-labeled oils met dexos 1 without any change in formulation. Initially, many blenders refused to pay the license fee for the logo, but almost every synthetic oil on offer already met the requirements of dexos 1. While dexos 1 was a step beyond API SN, it was only a small step.
 
Originally Posted By: fdcg27
While dexos 1 was a step beyond API SN, it was only a small step.
Based on what I remember from Lubrizol performance charts, it was not a small step at all.
 
Originally Posted By: Quattro Pete
[quote=fdcg27] While dexos 1 was a step beyond API SN, it was only a small step.
Based on what I remember from Lubrizol performance charts, it was not a small step at all. If you look at the numbers rather than a graphical depiction, the differences aren't all that great. This is the reason that virtually any Grp III qualified for dexos 1.
 
Originally Posted By: fdcg27
This is the reason that virtually any Grp III qualified for dexos 1.
While API SN oil could be group II, right?
 
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