Here is a great read by our own CRAZYDIESEL :)

[Rodslinger]

Since Rudolf Diesel Patented The Diesel engine in 1898, the Diesel engine has been widely recognized for it's reliability, low-end torque and higher efficiency than Gasoline engines. This is partially due to the Higher BTU rating of Diesel fuel (140,000BTU per gal. approx.) than Gasoline (125,000BTU per gal. approx.), but is also due to the fact that Diesel engines do not operate on a "set" fuel ratio, unlike Gasoline engines. Stoichiometric for a Gasoline engine is approximately 14.7 air :1 fuel (14.7:1) all the time when it is running. Diesel engine Stoichiometric however... is not as cut and dry. It can vary tremendously, depending on the exact type of fuel used, it's Cetane rating (readiness to ignite), the amount of moisture in the fuel, and the age of the fuel among many other factors. Because diesel engines do not have a throttle, the engine intakes as much as air as it wants on the intake cycle (I am omitting Turbocharged diesels for the time being), therefore, the fuel ratio cannot remain constant, like a Gasoline engine. The actual fuel ratios in a diesel engine can range anywhere from 100.0 available air :1 fuel (100.0:1) at idle with no load, all the way to as high as 10.0 air :1 fuel (10.0:1) at full governed speed with full load. The fuel ratio itself doesn't actually vary 100:1/10:1 like that, it's actually close to the 14.7:1 "most" of the time. The reason it is said that you have a fuel ratio of "100:1" is because, you have all the air available that the intake can suck, and the Turbo/Supercharger/s can boost.

Cylinder Contribution is also very, very important in the proper and smooth operation of a diesel engine. When at idle, your diesel engine may only be injecting a droplet of fuel approximately half of the size of a .177 caliber BB. Each cylinder must inject the exact amount of fuel that all of the others inject, to achieve smooth operation.
In a perfect world, every diesel engine's injectors would be perfectly clean, all the time. However, due to the composition of diesel fuel (and because this isn't a perfect world), over time the Injector Nozzles can and do, partially clog up with fuel deposits. The symptoms of clogged Injector Nozzles are, one or more cylinders seem louder than others, the engine does not idle smoothly, reduced power levels, and in extreme cases, excessive black smoke under load.

The injectors themselves in a Diesel engine are typically almost 100% reliable, but thousands are replaced each year needlessly, because of the aforementioned symptoms, when in 99% of cases, a fuel additive would have prevented the problem before it even started, or fixed the symptoms after they started.

There are literally dozens upon dozens of different diesel fuel additives out there. From brands such as Stanadyne, Power Service, Lucas Oils, Shell Rotella, STP, Gumout, and the list goes on and on.

There are also some very important factors to consider when purchasing an additive, especially with the advent of Ultra Low Sulfur Diesel Fuel (15ppm)

The Six most important factors when purchasing a diesel fuel

additive are:

1. Will it clean my injectors well?

2. Will it increase the Lubricity of my fuel(very important with the ULSD)

3. Is it SAFE?

4. Is it worth the cost, and does the product even work?

5. Will it harm my diesel fuel filter?

6. When will I have to add the product again?

Let's address the first factor first.

Will it clean my injectors well?
In Most Cases, Yes.

Most of the diesel fuel injector cleaners will have a Flora of chemicals such as Benzene, Toluene, Mineral Spirits, and Xylene. What these chemicals do to the fuel is nothing but increase the Cetane Rating of the fuel. The majority of the diesel fuel additives will have those chemicals in different and varying quantities.
The major purpose of the cetane boosting chemicals, is as soon as you put it in your Diesel Fuel Tank and drive down the road with it, you notice "hey it is running smoother" almost immediately. This is intentional, and gives a "shock and awe value" to the additive which will make you buy it again in the future.
Power Service Diesel Kleen and also Their Fuel Supplement is a good example of this. Not to say anything bad about their product, or any other product that contains the aforementioned chemicals, but "most" of the chemicals are

Diesel Fuel Additive manufacturers also will add a proprietary blend of detergents into the Additive that actually do the cleaning of the injectors (Which happens over the course of dozens of miles). Power Service Diesel Kleen also has a Teflon lubricity additive included in the detergent package, which also helps to quiet down the injector noise.

Products such as Lucas Oils Fuel Treatment (I personally use the Lucas Oils Fuel Treatment in my 99' Ford F-250 Power Stroke Diesel), totally skip the Cetane boosters, and give you nothing but the Detergent and Lubricity Package. This can be good, or depending on your view, a somewhat not so good thing. You will not have the sudden "oh wow it's running great" happen to your Diesel Powered Vehicle with Lucas Oils Fuel Treatment, however I do believe out of all of the products available, this one is one of the best for cleaning the fuel system.

I will admit that I am biased towards the Lucas Oil Fuel Treatment, however, I have tried everything from STP to GUMOUT (Truck actually ran worse on these two!) to Rotella T DFA, and nearly everything in between. Rotella T DFA does come in a very close second to the Lucas, and is not to be taken lightly, it is a very good product, however, is a bit hard to find.

I have also tried 2- stroke oil with very good results, although not for cleaning the Fuel System, 2-stroke oil quieted down the engine overall. I ran over 5,000 miles running the 2-stroke oil every fill-up (read the "2-stroke oil" article in the "Lubricity of Diesel Fuel" Section for more info)



Will it increase the Lubricity of my fuel?
With Most Products, Yes.



Most of all of the additives contain a variant on a Lubricity Package. Power Service happens to use Teflon in their products (their name for it is SlickDiesel, but a person I spoke with at Power Service told me it is a Teflon Derivative), and the Teflon stays behind for a period of time. Even after the additive has been ran through the fuel system and the fuel tank/s are re-filled, the Teflon stays behind and works it's wonders on the injector plungers, and other fuel system parts.

This is not to say other additives are bad at all, not in the least(with the exception of the STP and GUMOUT maybe). However, to my knowledge, no other additive, except for Lucas Oils Fuel Treatment, has a lubricity package that stays behind and continues to work after the product itself is long gone out of the fuel system.


Is it SAFE?
Yes, almost always.

All products, (except for off-brands you may find at mini-marts and surplus style stores) have to pass very rigorous tests before they are put on the market. A good example of this was December of 2006, when Power Service, and most of the other additive manufacturers pulled their product from store shelves, because they were not sure that their product would be compatible with the Tier II emissions standards, and the Diesel Particulate Filters that became mandated January 1, 2007.

The Manufacturers tested their products on the engines, and fuel systems in simulated tests, in severe conditions to ensure that their products would not harm the emissions equipment.


Is it worth the cost, and does the product even work?


With the exception of the STP and GUMOUT products, I feel that every product works well in it's own way, some products may work better in different types of engines, for instance the GUMOUT may work wonders in a 2-cycle Detroit Diesel, but it made my PSD run worse, which makes me biased against it.


Will It Harm My Diesel Fuel Filter?
Fat Chance, But Still Possible.


I have never had a filter clog up on me because of a product I ran through my truck, however, every truck is different, so you may want to check/change the filter soon after you run a Diesel Fuel Additive for good measure.



When will I have to add the product again?
Soon, Very Soon.

I recommend every 15,000 miles, or every 3rd oil change, whichever comes first, or if you begin to notice the engine not performing like it did after you added the additive last time.

The Main reason I say every 15,000 miles, is because most Diesel Vehicles require the Fuel Filter to be changed every 15,000 miles, so if you add the additive just before you are going to change the oil and fuel filter, then should the filter clog up because of junk that has come off of the walls of the Fuel Tank, and other surfaces, it will not be that big of a loss, as you were about to change the filter anyway.



If you've had a good, or bad experience with a product that I have, or have not listed here, I want to hear about it! e-mail me at xxxxxxxxxxxxxxxxxx.com with your vehicle specs, what product you used, how much you used, and what brand of product you used.



© Brian Elijah Hicks 2007

[Southpaw]

Great writup
I've had pretty good luck with 2-stroke oil for about 30,000 miles, but I just ordered a bottle of FT-10 from DPP. I'm going to give that a shot for a while.
The only thing that surprises me is that he only recommends treating your fuel every 15,000 miles? The therory makes sense, but I treat mine at evry fill-up.

[wustydemo]

What additive do you recommend for cleaning the injectors of a 2006 6.0L Powerstroke?

[95and05]

well i've had good luck with 2-cycle oil for over 100,000 and really notice when i didnt add it. i buy it in gallons by the case. but after this writup i might run some additive in my truck a little more often.