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Question about Dexos


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I have 2011 Sierra, 5.3, 4x4.  157k miles.  Oil changes have been done by the dealer using Dexos oil since I bought the truck used in 2019.  Runs fine, uses no  oil. 

 

I'm wondering if its necessary to use only Dexos oil with 157k miles on it.  I did one oil change myself some time back and put in Mobil 1. I'm not sure but it was either "extended mileage" or "high mileage" that I used.  I don't think it was Dexos.  It did fine; in fact the oil pressure seemed if I remember correctly to run a little higher than it had been, which always had been around 38-40 hwy speed and 22-25 idle. I'm due to change oil and thinking about going to Mobil 1 full synthetic or Castrol synthetic.  Does it hurt to not use a Dexos oil at this mileage ?  I need some knowledgeable input,

Edited by Jworks
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Nope, no warranty, so no DEXOS needed, unless you just really like the brand of oil, and it is DEXOS rated.

 

Have you used synthetic oil in the truck before? I have heard switching at that mileage may create leaks?

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Dexos gen 1 was a synthetic blend spec. That's what the factory fill in your truck was. Subsequent generations of Dexos have been a "full synthetic" spec. GM came up with the Dexos spec in response to the AFM problems. If you run a quality, full synthetic oil and filter, and change it every 5K miles (4K is better), it should be okay. Dexos-rated oil says so right on the bottles--you may already be using it, or it may cost the same as what you are already using. It only takes a minute to look in the oil aisle. 

Edited by MaverickZ71
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GM's dexos oils are spec'ed to help them to maintain low emissions while extending the intervals in between oil changes. While some iterations of the product do actually change the spec required for the oil to be able to be certified at a particular 'level', many of the recent changes are negligible. 

 

For your truck, any "dexos1" rated oil be perfectly fine so long as the viscosity is what your engine and conditions call for. And it's readily available in some places on the cheap where you might not realize. For example: Kirkland (Costco) and SuperTech (WalMart) branded oils that list dexos1 for certification are put out by Warren Distributing. They are a know quality company that produces a quality product, and I've seen tests done that show the effectiveness of both of the mentioned brands are identical to each other (which they should be, they're the same formulation).

 

The whole purpose of the spec is to have a target that oils can meet for your engine to operate well. Those companies that ponied up the cash to carry the badge of "certification" are known to meet the standard necessary.

 

dexos1 is currently at the Gen 3 spec level and that's fully backward compatible with ANY requirement for dexos1 oil. I run the Kirkland 0W-20 dexos1 Gen 2 oil in my wife's car and my prior truck. I also run the 5W-30 dexos1 Gen 2 oil in my Camaro SS. I suspect that the next time I buy either of those oils, Costco will have had their stock change over to the dexos1 Gen 3 certified oil.

 

gmdexos.com has the lists of which oils / viscosities are certified at the different specs.

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4 hours ago, Jworks said:

I have 2011 Sierra, 5.3, 4x4.  157k miles.  Oil changes have been done by the dealer using Dexos oil since I bought the truck used in 2019.  Runs fine, uses no  oil. 

 

I'm wondering if its necessary to use only Dexos oil with 157k miles on it.  I did one oil change myself some time back and put in Mobil 1. I'm not sure but it was either "extended mileage" or "high mileage" that I used.  I don't think it was Dexos.  It did fine; in fact the oil pressure seemed if I remember correctly to run a little higher than it had been, which always had been around 38-40 hwy speed and 22-25 idle. I'm due to change oil and thinking about going to Mobil 1 full synthetic or Castrol synthetic.  Does it hurt to not use a Dexos oil at this mileage ?  I need some knowledgeable input,

 

 

Dexos is not an oil.  Its a specification.  

 

99.9% of the gas engine oils on the market are Dexos 1 licensed so they meet the Dexos 1 specification.  Mobil 1, Castrol, Pennzoil, Valvoline, etc.  Boutique oils test and claim but don't pay for licensing so if you trust Amsoil's claims for example (and many do with no issues) then those are acceptable oils to run as well.   

 

Dexos 1 is 99% of gas engines.  Current spec is Dexos 1 Gen 3.  API spec SP, ILSAC GF-6A and Dexos all align at this point really.  Biggest push with Gen 3 specs are combating low speed pre ignition on direct injection NA and boosted gas engines.    

 

Edited by newdude
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I think it is interesting that people support GM engineering on Dexos approved oils, but do not trust the oil change interval recommendation (re. Oil Life Monitor).   PS-Dexos is a revenue stream for GM.

Edited by elcamino
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5 hours ago, elcamino said:

I think it is interesting that people support GM engineering on Dexos approved oils, but do not trust the oil change interval recommendation (re. Oil Life Monitor).   PS-Dexos is a revenue stream for GM.

 

It's a big revenue stream for them, and they know how to milk it.


Example:

 

The LT1 motor in the Camaro was originally filled with 5W-30 dexos1 from the factory when the car released in 2016. The High Performance Supplement outlined track prep for the car to include changing the oil to 0W-40 dexos2. Given the different operating characteristics on the track, the change to a different spec oil is reasonable. 

 

Somewhere in either 2019 or 2020, the lawyers got involved and reversed the requirements and the process to where the engine is factory filled with dexos2 and the dexos1 oil is acceptable to meet warranty requirements "for street use."

 

Then GM saw the opportunity for money and they created dexosR which is essentially dexos2 all over again. The 2023 and 2024 model years say that the dexosR oil is the recommended one (note the lack of use of the word "Required") while the 5W-30 dexosR is again acceptable to meet warranty requirements "for street use."

 

So... go try and buy 5W-30 dexosR oil anywhere. I'll wait. It literally doesn't exist but GM has been telling people for at least two years that they can use it. Huh?

 

This is a prime example of Mobil and GM being in bed together to create artificial specs to make money - GM gets the money from companies that pay to carry the certified badge and the oil manufacturers get to charge stupid prices for their oil. Mobil1 Supercar 0W-40 dexosR commonly sells for $10+ per quart while I can buy "any old" 5W-30 dexos1 oil for about $4 per quart. And since the LT1 motor has not changed internally to where the ACTUAL requirements of the engine for oil is still exactly the same, there's no reason that someone can't run the cheaper oil "for street use."

 

TL;DR - GM makes a lot of money off of oil companies that pay to get their oil branded and listed as certified to a specific dexos spec and they have learned to create "new" specs instead of refreshing an existing one to create a new "Gen" of that spec (like they did with dexos1) because it creates more confusion among the consumers and they spend more money.

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3 hours ago, ember1205 said:

This is a prime example of Mobil and GM being in bed together to create artificial specs to make money

 

Phillips 66 since 2021 [note section 1]

 

Dexos SDS.pdf (seattleautomotive.com)

 

Someone schooled me on this a few months ago. 😏

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12 minutes ago, Grumpy Bear said:

 

Phillips 66 since 2021 [note section 1]

 

Dexos SDS.pdf (seattleautomotive.com)

 

Someone schooled me on this a few months ago. 😏

 

That is calling out who makes the dexos1 oil that is branded ACDelco, though. My point was that Mobil1 is the only oil on the market available with the dexosR spec currently and they were the first (or very near the first) oil available at each of the various dexos spec levels. In other words, Mobil and GM are working together to create the specs initially, get the Mobil oils certified, and sell the oil for premium pricing. GM gets their fees for 'selling' the certification to Mobil and Mobil recoups it by being the only product available with the cert for a period of time.

 

I would bet that is also when the Gen3 version of dexos1 became "a thing" as they needed to justify having a different company provide the ACDelco-branded version of it.

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19 hours ago, ember1205 said:

GM's dexos oils are spec'ed to help them to maintain low emissions while extending the intervals in between oil changes. While some iterations of the product do actually change the spec required for the oil to be able to be certified at a particular 'level', many of the recent changes are negligible. 

 

For your truck, any "dexos1" rated oil be perfectly fine so long as the viscosity is what your engine and conditions call for. And it's readily available in some places on the cheap where you might not realize. For example: Kirkland (Costco) and SuperTech (WalMart) branded oils that list dexos1 for certification are put out by Warren Distributing. They are a know quality company that produces a quality product, and I've seen tests done that show the effectiveness of both of the mentioned brands are identical to each other (which they should be, they're the same formulation).

 

The whole purpose of the spec is to have a target that oils can meet for your engine to operate well. Those companies that ponied up the cash to carry the badge of "certification" are known to meet the standard necessary.

 

dexos1 is currently at the Gen 3 spec level and that's fully backward compatible with ANY requirement for dexos1 oil. I run the Kirkland 0W-20 dexos1 Gen 2 oil in my wife's car and my prior truck. I also run the 5W-30 dexos1 Gen 2 oil in my Camaro SS. I suspect that the next time I buy either of those oils, Costco will have had their stock change over to the dexos1 Gen 3 certified oil.

 

gmdexos.com has the lists of which oils / viscosities are certified at the different specs.

Thank you for that link.  Wow, it seems virtually everything out there any of us would use is licensed .  Looking through that list it looks like everything is certified. I'm perplexed though on why some oils (lets say Mobil 1 for example) have the Dexos1 on the can and others don't.  Thats what I don't get.

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2 minutes ago, Jworks said:

Thank you for that link.  Wow, it seems virtually everything out there any of us would use is licensed .  Looking through that list it looks like everything is certified. I'm perplexed though on why some oils (lets say Mobil 1 for example) have the Dexos1 on the can and others don't.  Thats what I don't get.

 

That's where it really gets confusing, If the logo is present, it should also contain the License Number for its certification. You can look that number up on the dexos site. There does not appear to be any other way to cross-reference products. Going purely by the viscosity and descriptors, it would seem that "everything" has been verified. But the lack of logo on the  package says it hasn't actually passed the testing.

 

Any company that ponied up the money to get the certification done would almost certainly be advertising the logo to generate more sales...

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2 hours ago, ember1205 said:

 

That's where it really gets confusing, If the logo is present, it should also contain the License Number for its certification. You can look that number up on the dexos site. There does not appear to be any other way to cross-reference products. Going purely by the viscosity and descriptors, it would seem that "everything" has been verified. But the lack of logo on the  package says it hasn't actually passed the testing.

 

Any company that ponied up the money to get the certification done would almost certainly be advertising the logo to generate more sales...

 

Red Line is owned by Phillips. The HP line does not have the logo. The Professional series does. The HP series does show in the compatibility cross references under suitable replacement for;  Dexos Gen2. Gen3 and D. Pretty sure Phillips 66 has a clue about what will and what will not pass the performance test. Yet they do not have a license for this product line 🤔

 

Why? Passing a performance test isn't the only reason a fluid would be incapable of gaining a license. There are also limits on things like base oil CHOICE or additive limits to name the most obvious. Especially the first two generations. 

 

It would be unwise to assume that a higher performing base oil or more than the minimum requirement add rate giving a better performing fluid was inferior because it didn't conform to the license restricted choices.

 

That would be like an insurance company refusing to pay a brain surgeon because he was educated at the University of Washington that ranks 1st and not at their preferred choice, Ohio State ranked 40th. 2023-2024 Best Medical Schools (Primary Care) - US News Rankings

 

While the license program certainly prevents out right garbage oils from receiving a logo based on poor performance it also eliminates over achievers whose choices outperform based on raw materials restrictions. 

 

 

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45 minutes ago, Grumpy Bear said:

 

Red Line is owned by Phillips. The HP line does not have the logo. The Professional series does. The HP series does show in the compatibility cross references under suitable replacement for;  Dexos Gen2. Gen3 and D. Pretty sure Phillips 66 has a clue about what will and what will not pass the performance test. Yet they do not have a license for this product line 🤔

 

Why? Passing a performance test isn't the only reason a fluid would be incapable of gaining a license. There are also limits on things like base oil CHOICE or additive limits to name the most obvious. Especially the first two generations. 

 

It would be unwise to assume that a higher performing base oil or more than the minimum requirement add rate giving a better performing fluid was inferior because it didn't conform to the license restricted choices.

 

That would be like an insurance company refusing to pay a brain surgeon because he was educated at the University of Washington that ranks 1st and not at their preferred choice, Ohio State ranked 40th. 2023-2024 Best Medical Schools (Primary Care) - US News Rankings

 

While the license program certainly prevents out right garbage oils from receiving a logo based on poor performance it also eliminates over achievers whose choices outperform based on raw materials restrictions. 

 

 

 

I never said the entire program made SENSE. lol

 

Folks need to understand that the dexos cert program is FIRST AND FOREMOST a money program for GM. It generates revenue for them AND it gives their lawyers a line of defense for denying warranty claims (thus, saving them money). It has the SECONDARY use of providing a list of oils known to "not break" the engine.

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