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For me, cost of adding additional additives is not the reason for not using them.
I see people reply with "its cheap insurance, or it cant hurt" I am not sure that adding additional additives to a fuel that already has them is good. The tendency to add a little more than recommended is a concern, or adding the rest of the bottle since it is open. I wonder what the overdosing of additives is doing to sensors and other fuel components?
There are so many contradictions to the diesel supplement too that made it very confusing to me.
I wanted to do the right thing, but was unable to purchase the gm additive from my 3 local dealers which did not even stock it. The contradiction of not using a non gm branded additive contradicts even more.
I have decided to leave the dosing of additives to the engineers of my major fuel supplier and not worry about it.
I am at 9700 miles and it sounds like a diesel, good enough for me.
 

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For me, cost of adding additional additives is not the reason for not using them.
I see people reply with "its cheap insurance, or it cant hurt" I am not sure that adding additional additives to a fuel that already has them is good. The tendency to add a little more than recommended is a concern, or adding the rest of the bottle since it is open. I wonder what the overdosing of additives is doing to sensors and other fuel components?
There are so many contradictions to the diesel supplement too that made it very confusing to me.
I wanted to do the right thing, but was unable to purchase the gm additive from my 3 local dealers which did not even stock it. The contradiction of not using a non gm branded additive contradicts even more.
I have decided to leave the dosing of additives to the engineers of my major fuel supplier and not worry about it.
I am at 9700 miles and it sounds like a diesel, good enough for me.
Just a couple of points since you may not be seeing the whole picture. First, though, you'll likely be just fine not running additives as I'm sure the majority of owners don't and we're not seeing tons of failures, so don't take these posts as you doing harm by not using them.

That said, fuel distributors aren't going to add more lubricity or cetane improvers than are necessary to ensure the fuel meets minimum requirements. There is no advantage for them to add any more than necessary because that's extra cost for them that isn't reflected at the pump. The exception to this would be "premium" diesel that some chains sell that do contain additional lubricity and cetane improvers and they charge a higher price per gallon for it vs standard diesel.

Overdosing additives is not really a problem unless you try really hard. Worrying about overdosing because you don't know how much additive is in the fuel that comes out of the pump is overthinking things. The additive dosing isn't and doesn't have to be exact and many products have 2 different doses you can do depending on what you want out of the product.

So, operating on the assumption that what comes out of the pump is only meant to meet the minimum requirements and that dosing doesn't need to be exact you can see that using quality additives at the ratio they specify won't be an issue. What is an issue is fuel that barely meets the requirements. I can tell you from experience that it's very easy for me to tell when I get low quality fuel. The diesel sound you hear isn't necessarily a good thing and poor quality fuel will make your truck sound even more like a diesel because the cetane number is low. Using a quality additive like Power Service Diesel Kleen or Hot Shot's Secret Everyday Diesel Treatment will add lubricity, increase the cetane number, and help clean up the fuel system. More lubricity is never a bad thing. Increasing the cetane number by single-digits won't hurt a thing.

For reference, the minimum cetane number required in the US is 40. In Europe the minimum cetane number is 51. The highest allowed in Europe is 60. That's rather arbitrary, though. In Finland, the minimum cetane number allowed is 60 with some up to 70.

You can see that by other standards our fuel in the US is pretty awful when it comes to cetane and cetane is basically what determines how well a diesel runs. As the cetane number goes up the diesel rattle comes down and throttle response also improves.

So, don't overthink it. Using a quality additive in the correct dose will not hurt a thing and will provide a number of improvements. Are they required? Not if you fill with consistently "good" fuel, the problem is you won't know if you got some low quality fuel until you notice the diesel rattle becomes more prominent. I got some low quality diesel in upstate NY once, my truck rattled like nobody's business when starting from a stop and I happened to run out of additive earlier in that trip, so I picked some up later that day and shortly thereafter my engine was back to what I consider to be normal.

Quality additives also won't affect your warranty.
 

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Sulfurs contribution to lubricity is not zero but you are right, the process of removing it causes the greatest reduction in lubricity.
I know we're pretty much on the same page, I just feel like there's so much misinformation on this subject that it warrants clarification and nipping the "sulfur adds lubricity to diesel fuel" claims in the bud.

When it comes to diesel fuel, sulfur does not add lubricity. Sulfur has been used as part of EP grease additive packs, but for all intents and purposes the sulfur in diesel is not and has never been the source of the fuel's lubricity. There is soooo much misinformation out there on the internet, largely coming from sites trying to sell products, that claim sulfur is what gives diesel its lubricating properties and it drives me nuts. In diesel fuel I'm not going to feed that misinformation by saying that sulfur plays a role in the fuel's lubricity because it really doesn't, not to any meaningful degree, and as such it is effectively zero. One such example of this nonsense is...

Low sulfur diesel could have up to 500 parts per million (ppm). ULSD allows for just 15 ppm. That's a 97 percent reduction. While the reduced sulfur is good for the environment, it's also a 97 percent reduction in the element that gives petroleum diesel its lubricating properties.
Which is complete hogwash and is not based on the science, merely a misunderstanding of the role sulfur plays and what actually causes the reduction in lubricity. The above quote from a product vendor is just one example of many where they don't bother to understand the science and think correlation is causation.

In reality...

As low sulphur emissions became mandatory, fuel refiners have had to develop new technologies to reduce the sulphur content in order to meet the emission standards. The issue is in the refining process used to remove the sulphur. The most cost effective way is to use a chemical process called hydro-processing. During hydro-processing the sulphur in the fuel is removed and replaced by hydrogen resulting in a cleaner burning fuel with improved performance. Unfortunately as hydrogen is a highly reactive element it also reacts with other components in the fuel removing the polar and aromatic compounds that provide conventional diesel fuel with adequate lubricating capability.
 

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The tendency to add a little more than recommended is a concern, or adding the rest of the bottle since it is open.
Not really an issue for me. For the brand I use the smallest bottle would treat two tanks, but the larger bottles are much less expensive per ounce. Given that I would suspect what most users do is the same as me. Buy the larger size and fill the smaller bottle to the appropriate level before buying fuel.

I should probably look to see if there are on-line options to buy multiple smaller bottles more cheaply, but the current prices at O'Reilly APs are:

16 ounce: $9.99
32 ounce: $11.99
80 ounce, 19.99 (80 ounces would treat about 10 tanks).
 

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Just a couple of points since you may not be seeing the whole picture. First, though, you'll likely be just fine not running additives as I'm sure the majority of owners don't and we're not seeing tons of failures, so don't take these posts as you doing harm by not using them.

That said, fuel distributors aren't going to add more lubricity or cetane improvers than are necessary to ensure the fuel meets minimum requirements. There is no advantage for them to add any more than necessary because that's extra cost for them that isn't reflected at the pump. The exception to this would be "premium" diesel that some chains sell that do contain additional lubricity and cetane improvers and they charge a higher price per gallon for it vs standard diesel.

Overdosing additives is not really a problem unless you try really hard. Worrying about overdosing because you don't know how much additive is in the fuel that comes out of the pump is overthinking things. The additive dosing isn't and doesn't have to be exact and many products have 2 different doses you can do depending on what you want out of the product.

So, operating on the assumption that what comes out of the pump is only meant to meet the minimum requirements and that dosing doesn't need to be exact you can see that using quality additives at the ratio they specify won't be an issue. What is an issue is fuel that barely meets the requirements. I can tell you from experience that it's very easy for me to tell when I get low quality fuel. The diesel sound you hear isn't necessarily a good thing and poor quality fuel will make your truck sound even more like a diesel because the cetane number is low. Using a quality additive like Power Service Diesel Kleen or Hot Shot's Secret Everyday Diesel Treatment will add lubricity, increase the cetane number, and help clean up the fuel system. More lubricity is never a bad thing. Increasing the cetane number by single-digits won't hurt a thing.

For reference, the minimum cetane number required in the US is 40. In Europe the minimum cetane number is 51. The highest allowed in Europe is 60. That's rather arbitrary, though. In Finland, the minimum cetane number allowed is 60 with some up to 70.

You can see that by other standards our fuel in the US is pretty awful when it comes to cetane and cetane is basically what determines how well a diesel runs. As the cetane number goes up the diesel rattle comes down and throttle response also improves.

So, don't overthink it. Using a quality additive in the correct dose will not hurt a thing and will provide a number of improvements. Are they required? Not if you fill with consistently "good" fuel, the problem is you won't know if you got some low quality fuel until you notice the diesel rattle becomes more prominent. I got some low quality diesel in upstate NY once, my truck rattled like nobody's business when starting from a stop and I happened to run out of additive earlier in that trip, so I picked some up later that day and shortly thereafter my engine was back to what I consider to be normal.

Quality additives also won't affect your warranty.
Thank you Drax! This is great information and I have definitely over thought this. I appreciate that you took the time to explain it in detail.
https://www.coloradofans.com/javascript:void(0)
 

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After having my engine replaced due to a failed inj, I asked the service advisor at my dealership about using fuel additives. I mentioned that in the manual, it said that GM doesn't recommend using additives, and he told me that they don't say not to anymore, and that he recommended to use a fuel additive, and he didn't specify any particular brand, but definitely use an additive.
 

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I don't know if it adds much but I had had my oil sampled a few times. The last time was 10K miles prior to the piston failure. The samples were all in the normal range.
If there was excessive wear due to the oil I would have expected it to have shown up on that.
At the time of the failure, the oil had about 2K miles on it.
 

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For what it is worth, the 2020 2.8L Duramax supplement specifically states that they do not recommend using fuel additives.
You need to look again, below is what it says. You can ignore the part about them not recommending other aftermarket additives because that would involve GM endorsing products that don't have their name on it, something GM doesn't have a habit of doing. So, ignoring "use only GM additves" which GM doesn't even make, the takeaway is that you should be using additives unless you're using Top Tier diesel which is only available at a handful of stations in the US.

Fuel Additives
TOP TIER Detergent Diesel is
highly recommended for use with
your vehicle. If your area does not
have TOP TIER Detergent Diesel,
GM recommends the use of
ACDelco Diesel Fuel Conditioner.
This will help maintain optimal
engine performance. GM does not
recommend other aftermarket diesel
additives.
If low-quality diesel is used for
refueling, GM recommends adding
ACDelco Fuel System Treatment
Plus-Diesel to help clean engine
deposits. This is available only at
your GM dealer.
 

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You need to look again, below is what it says. You can ignore the part about them not recommending other aftermarket additives because that would involve GM endorsing products that don't have their name on it, something GM doesn't have a habit of doing. So, ignoring "use only GM additves" which GM doesn't even make, the takeaway is that you should be using additives unless you're using Top Tier diesel which is only available at a handful of stations in the US.
No need to look again, I saw that the first time.
I suppose if one can chooses what to ignore you make it say most anything you want it to.
I don't have a strong opinion on the use of additives either way but GM it is pretty clear about it.
Is GM's interpretation of "Top Tier" the stuff that is only available in a handful of stations? I would take that to mean the top tier available from major producers at mainstream stations. It would be odd for them to recommend only using fuel that most of use don't have access to.
 

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No need to look again, I saw that the first time.
I suppose if one can chooses what to ignore you make it say most anything you want it to.
I don't have a strong opinion on the use of additives either way but GM it is pretty clear about it.
Is GM's interpretation of "Top Tier" the stuff that is only available in a handful of stations? I would take that to mean the top tier available from major producers at mainstream stations. It would be odd for them to recommend only using fuel that most of use don't have access to.
Top Tier is a trademarked name that GM owns part of and helped develop, it is a very specific thing and not just a reference to only using name-brand fuel.


Regarding the use of additives, you're welcome to interpret what GM has said any way you like, but in no way, shape, or form does the diesel supplement state that GM does not recommend the use of additives. It's very clearly the opposite, use additives unless you use Top Tier diesel. If you use extra-crappy fuel then there's a different "GM" additive they recommend.

I know how GM operates when it comes to specs and recommendations. They only recommend products from companies that have paid GM to put GM's specs or name on the bottle. dexos1, dexos2, dexosD, these are all GM specs that require licensing in order to be put on the bottle. The "GM" fuel additives that are mentioned in the diesel supplement are not made by GM, they are an aftermarket additive that has been rebranded as a GM product. There is nothing special about these additives compared to any of the other quality additives available other than the other products don't have GM's name on them so GM doesn't make any money. As I said, GM won't recommend any products that they don't control.

If you don't want to use additives then that's your choice, but GM clearly states the use of additives is recommended if you can't use Top Tier diesel.
 
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No need to look again, I saw that the first time.
I suppose if one can chooses what to ignore you make it say most anything you want it to.
I don't have a strong opinion on the use of additives either way but GM it is pretty clear about it.
Is GM's interpretation of "Top Tier" the stuff that is only available in a handful of stations? I would take that to mean the top tier available from major producers at mainstream stations. It would be odd for them to recommend only using fuel that most of use don't have access to.
So far GM hasn't taken the route of warranty denial on fuel systems for our trucks too much: saying you used poor quality fuel not our problem. But whats in the manual is their non liability way of saying US diesel fuel is causing too many failures on our HP fuel systems.

If most suppliers were doing top tier diesel it would say it on their pumps and be on the list, they are not.
 

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I don't know if it adds much but I had had my oil sampled a few times. The last time was 10K miles prior to the piston failure. The samples were all in the normal range.
If there was excessive wear due to the oil I would have expected it to have shown up on that.
At the time of the failure, the oil had about 2K miles on it.
Your referencing of an oil analysis above has absolutely nothing to do with the topic at hand. This is about fuel quality based on it's ability to lubricate your high pressure fuel pump and the cetane rating for a cleaner burn protecting your emission systems.

Even GM acknowledges Top Tier versus non Top Tier. They don't come right out and say Top Tier versus low quality fuel because they'd get sued up the wazoo but lets face it if you're not Top Tier then you're a lower quality fuel as defined by GM. The Top Tier is trademarked and as such if your supplier isn't on the list and have a Top Tier label affixed on the pump it's not as good of quality fuel.

This is the point of using an additive, it puts you back into the Top Tier realm of fuel quality.

The take away,
GM acknowledges using quality Top Tier fuel is required. The choice is Top Tier or the other stuff.
Using anything other then Top Tier trademarked labeled fuel you should use and additive to protect your investment.

Europe has higher fuel standards then NA does and they don't have the amount of failures we do.

Like I said previously dump one in your tank and you will see how much quieter the engine is and how light throttle response is improved.
 

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Your referencing of an oil analysis above has absolutely nothing to do with the topic at hand.
Take a look at the title of the post. Look at the overwhelming majority of the individual posts. Take a look at the overwhelming majority of the posts over the past 2 months or so.
It actually has nothing to do with fuel quality-fuel quality is the tangent. If you are concerned with keeping the topic pure, you should not be talking about fuel quality.
 

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The take away,
GM acknowledges using quality Top Tier fuel is required. The choice is Top Tier or the other stuff.
Using anything other then Top Tier trademarked labeled fuel you should use and additive to protect your investment.

Europe has higher fuel standards then NA does and they don't have the amount of failures we do.

Like I said previously dump one in your tank and you will see how much quieter the engine is and how light throttle response is improved.
GM recommends top tier fuel, they don't require it.
As others have pointed out, "Top Tier" is a licensed term, that a diesel fuel is not labeled as such does not mean that it is inferior to one that is.
There is no guarantee that an additive will bring the fuel quality up to "top tier" levels. If it was that easy wouldn't we see a lot more "Top Tier" diesel?
Europe also does not have a lot of 400+ HP diesel trucks running around, many of which are significantly modified. I have not seen that similar versions of vehicles have had much trouble in the US.
All of these responses are putting words in GM's mouth, yet they have laid it out in black and white-they don't recommend other aftermarket diesel additives. If people want to use additives, go ahead but why try to justify it?
I've used additives in my Cummins-haven't really noticed a difference. Perhaps I'll try it out in my Colorado. Current noise and throttle response have not really left me wanting however.
 

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Top Tier is a trademarked name that GM owns part of and helped develop, it is a very specific thing and not just a reference to only using name-brand fuel.


Regarding the use of additives, you're welcome to interpret what GM has said any way you like, but in no way, shape, or form does the diesel supplement state that GM does not recommend the use of additives. It's very clearly the opposite, use additives unless you use Top Tier diesel. If you use extra-crappy fuel then there's a different "GM" additive they recommend.
This is what they say:
"Fuel Additives: TOP TIER Detergent Diesel is highly recommended for use with your vehicle. If your area does not have TOP TIER Detergent Diesel, GM recommends the use of ACDelco Diesel Fuel Conditioner. This will help maintain optimal engine performance. GM does not recommend other aftermarket diesel additives. If low-quality diesel is used for refueling, GM recommends adding ACDelco Fuel System Treatment Plus-Diesel to help clean engine deposits. This is available only at your GM dealer."
That clearly states in both shape and form that they do not recommend aftermarket fuel additives. GM supplied yes.
 

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As others have pointed out, "Top Tier" is a licensed term, that a diesel fuel is not labeled as such does not mean that it is inferior to one that is.
There is no guarantee that an additive will bring the fuel quality up to "top tier" levels. If it was that easy wouldn't we see a lot more "Top Tier" diesel?
Correct, but not being Top Tier does lead to uncertainty. As to the second point, Top Tier is also about storage and handling practices, so yeah, additives won't correct bad practices. From the first part of the DTT webpage

Must meet the stringent standards of the TOP TIER™ Diesel Fuel Performance Standard, including best practice housekeeping to minimize particulate and water contamination.
 

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That clearly states in both shape and form that they do not recommend aftermarket fuel additives. GM supplied yes.
Again correct, but they do not recommend against either, at least wholesale. They do in the 2019 diesel supplement recommend against certain additives, specifically:

Aftermarket diesel fuel additives, which contain alcohols, organo-metallic additives, or water emulsifiers.
 
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