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I like Optilube's "Summer" as it is reasonably inexpensive, has great lube qualities, cleans the system, and adds cetane. "Summer" does not do anything about water, but I don't look to my additive to deal with water, the fuel filters are designed to do that.
Correct about the role of filters and water. Also, per the item I just posted GM recommends against additives that deal with water.
 

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Correct about the role of filters and water. Also, per the item I just posted GM recommends against additives that deal with water.
For what is is worth and knock on wood I suppose, I do my own fuel filter servicing and have never found so much as a drop of water in the filter box. I drain it via the infamous yellow plug into a clean receptacle, do the service and pour the fuel back into the tank. I buy from the cheapest and busiest station in town.
 
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For what is is worth and knock on wood I suppose, I do my own fuel filter servicing and have never found so much as a drop of water in the filter box. I drain it via the infamous yellow plug into a clean receptacle, do the service and pour the fuel back into the tank. I buy from the cheapest and busiest station in town.
I've yet to have to change mine, being at only 25,000 miles. But when you do aren't you supposed to turn the key on without starting the engine, or some such thing, to allow the system to fill the filters and clear out the air? I would imagine not doing whatever is required could lead to high pressure fuel pump damage.
 

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I've yet to have to change mine, being at only 25,000 miles. But when you do aren't you supposed to turn the key on without starting the engine, or some such thing, to allow the system to fill the filters and clear out the air? I would imagine not doing whatever is required could lead to high pressure fuel pump damage.
Yes, that is correct. Prime the fuel system after installing the new filters. As I recall it is done 3 times, turn ignition to ‘on’ (without starting) for 30 seconds each time.
I did mine @ 29,000 miles - IIIRC had 17% life remaining. I was changing the engine oil and just decided to go ahead with changing the fuel filters.
 
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You either have a short memory or forgot you said this.

For what it is worth, the 2020 2.8L Duramax supplement specifically states that they do not recommend using fuel additives.
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.
You're also twisting what GM is saying. GM not recommending OTHER aftermarket additives is GM only endorsing the one with their name on it that they don't even manufacture. It's obvious when you take the whole thing in context that GM RECOMMENDS additives when not using Top Tier diesel but they will only "recommend" (endorse) the ACDelco-branded one. GM does not say to don't use additives. GM will not ever recommend BRANDS that aren't their own. Thus...they only recommend the ACDelco-labeled additive.

Cummins is an example of a manufacturer that recommends/endorses a non-Cummins/non-Fleetguard additive; PowerService Diesel Kleen. For years Cummins wouldn't recommend/endorse any aftermarket additives and then within the past few years or so they went with PowerService.

So now you have Cummins recommending PowerService, GM recommending the ACDelco-labeled additive, Ford selling their own lubricity + cetane improver and recommending it if you get poor-quality fuel...

Use Motorcraft® cetane booster or an equivalent cetane booster additive if you suspect fuel has low cetane. Use Motorcraft® anti-gel & performance improver or an equivalent additive if there is fuel gelling.
Do not use alcohol-based additives to improve cetane quality, to prevent fuel gelling or any other use. The use of alcohol additives may result in damage to the fuel injectors and system.
Ford also recommends Top Tier diesel.

So that's all 3 US automakers recommending and/or selling fuel additives to address fuel quality issues when not using Top Tier diesel. Why? Because fuel quality in the US is pretty awful, the Bosch CP4.2 pumps have a high failure rate in the US, and as a result they've all switched away from NOT recommending additives to recommending them with poor quality or non-Top Tier diesel.

Context is key and you seem to be selectively choosing words to suit your argument.
 
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I've yet to have to change mine, being at only 25,000 miles. But when you do aren't you supposed to turn the key on without starting the engine, or some such thing, to allow the system to fill the filters and clear out the air? I would imagine not doing whatever is required could lead to high pressure fuel pump damage.
Yes, and it takes a while. You can tell by the sound of the lift pump when it is done, as it is loud AF until it is done :LOL:
 

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You either have a short memory or forgot you said this.
Yes, my statement you quoted should have stated aftermarket diesel additives. That is my mistake.

"GM does not recommend other aftermarket diesel additives." This is all I have ever intended to state. Straight from the manual. It is right there in black and white. No word twisting needed.
That they went out of their way to state that should mean something. They would have simply said nothing if it did not matter.
To infer that they intend that you will use an aftermarket additive anytime top tier fuel is not available (which, as others have pointed out is not available to the majority of the market) is a stretch.
 

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If I were a betting man I'd wager it's injector tip failure and you now have a hole in the #4 piston which is allowing the pressure from the turbo and the fuel from the injector to flow right into the crankcase, diluting the oil and over-pressurizing the crankcase which has blown out a seal.


Definitely keep us posted! What a pain. :(
Same exact thing happened to me.
 

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Yes, my statement you quoted should have stated aftermarket diesel additives. That is my mistake.

"GM does not recommend other aftermarket diesel additives." This is all I have ever intended to state. Straight from the manual. It is right there in black and white. No word twisting needed.
That they went out of their way to state that should mean something. They would have simply said nothing if it did not matter.
To infer that they intend that you will use an aftermarket additive anytime top tier fuel is not available (which, as others have pointed out is not available to the majority of the market) is a stretch.
I use diesel fuel additives religiously for all my vehicles as I can see they absolutely do have beneficial effects, however I don't think they make a significant difference UNLESS you have consistently poor fuel quality as the additive can counter some of the negative effects like water, corrosion and deposits which could cause the injector to fail.. These are solenoid injectors instead of piezoelectric and solenoids do fail regularly however the units on the 6.6 don't have the same issues, so It's got to be endemic to the 2.8 units IMO. I think Piezo are more reliable and better design.

The exclusionary language about fuel additives is standard boilerplate CYA by GM. They can't say which ones are endorsed because there are so many and the formulas are constantly changing. So the only one is the AcDelco which can be standardized to meet their QC.

Most additives are basically chemicals made by other companies like Afton, Lubrizol, Mobil, Etc.. and sold in bulk to additive companies. They are blended together in varying concentrations in a standard base which typically includes aromatic hydrocarbons. Any legit additive that actually works will have transparent language and definitive expected results of each advertised property or beneficial effect. MOST DO NOT and use vague language to sell the product. Anything claiming to be a "Secret" probably isn't going to be transparent.
 
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