Diesel Fuel Additives/Conditioners - Good Stuff or Snake Oil

I see a lot of diesel fuel conditioners out there - Power Service, Lucas, etc. When I drove my Deuce 250 miles home from Selfridge ANG Base in Michigan, I added a quart of Power Service Fuel Conditioner and Injector Cleaner to the fuel, figuring it can't hurt and might help. The next tankful I went with Power Service Diesel Klean, since the label stated it was a more of a fuel system and injector cleaner, while the other product was more of a fuel conditioner and cold weather anti-gell treatment with some cleaning properties.

My question is, do these products provide enough benefits to justify the added cost. At $7.00-$8.00 per quart, which usually treats 100 gallons of fuel, that adds another 7 to 8 cents per gallon to the already high cost of diesel fuel!

Is it worth using these products or am I just throwing money away? At $2.66/gallon, the current price for diesel around here, I'd need to improve my mileage by .3 mpg just to break even. Would I be better off spending the money to just have my injector nozzles cleaned and adjusted? Or are there other benefits to using these products beyond mileage improvement? There seems to be many places selling a an awful lot of these products; why are they so widely used?

I use Bio-Con to kill the bacteria and algae that grow in diesel.

The FM-9-207 "Operation and Maintenance of Ordnance Material in Cold Weather (0 to -65F)" states that "Inhibitor, icing, fuel systems" should be used at a rate of one pint/40 gallons. "Add prior to refuling" for proper mixing.

The chemical is ethylene glycol monomethyl ether.
Hmm..maybe some unwashed biodiesel does the job.

Personally, I have never used any additive (other than biodiesel). Not cold enough for any length of time here in Virginia.
Did get some Bio-kleen (sp) to use with the biodiesel, but haven't used it yet.

Note: Alcohol in diesel will change the cetane value of the fuel.

The injector shop near me refers to injector cleaner as "tune up in a can"... Every now and again, when the truck(s) seem sluggish, I dump a bottle of Power Service or Stanadyne labeled injector cleaner into the tank... Used to do the same once every six months or so with Techron in my gas powered VW until I replaced it with a newer one that required premium (which already has a higher dose of Techron or similar added to it at most places compared to low grade).

Biocide is something that I think about using in my diesel tanks, but I never seem to get around to adding it and since the stuff comming out the bottom of my filters is pretty clean, I figure that I don't need it...

I suspect that in large part it depends on the quality of the fuel in your area as to whether it really makes a big enough difference to be worth it, that and your driving and use habits. I've got a couple of buddies who work Fords and Dodges with the Powerstrokes and Cummins engines very hard (haul heavy equipement on goosenecks, etc.) and they claim to have the numbers to show that they are doing better with additives then without (using Stanadyne stuff mostly, but occaisionally RACOR brand...).

I just tried some lucas in my car. The injectors must have been dirty because it really pirked the car up. It also cut the black smoke in half. I haven't checked to see if the milage increased. It probally went down because i keep my foot in it now with the extra power.

Speaking just for my 6.5, the Stanadyne Blue formula increased my MPG by about 1.5. In the end the cost balanced itself right out but the seat of the pants power was worth it. Stanadyne Blue has a cetane booster where the Stanadyne Red formula is more of a lubricity enhancer.

Fuel Additives

This is a bulletin from GM on fuel additives. Whatever you use, just be sure it doesn't have any emulsifiers in it, such as alcohol, which suspend water in the fuel and therefore bypass the operation of a typical water separator. GM finally released their own fuel conditioner, which I believe is made by Racor, but there are other brands which don't use emulsifiers. Standadyne and Racor are the only ones that I know of for sure, but others may be good too. As far as gelling, the fuel distributors already mix #1 and #2 diesel, regionally, to prevent this. So unless it gets way below 0 F, you shouldn't have a problem-at least I haven't. For the fungi growth, this is usually related to warmer weather and it requires some amount of water in the fuel for it to be active; so keep your tanks on the full side and get your fuel from high volume stations when possible to prevent this. Bottom line is, keep the water out and separate whatever may gets in there, and you shouldn't have any problems. Here is the bulletin.

Subject: Information on Diesel Fuel Additives #03-06-04-017B - (09/07/2005)


Models: 2006 and Prior Light Duty and Medium Duty Trucks

2006 and Prior Isuzu Commercial Medium Duty Models

2006 and Prior HUMMER H2

with 6.5L, 6.6L, 7.2L or 7.8L Diesel Engine (VINs F, P, S, Y, 1, 2, B,
3 --
RPOs L65, L49, L56, L57, LB7, LLY, LC8, LG4)


This bulletin is being revised to add model years, enhance the content and
add GM diesel fuel conditioner. Please discard Corporate Bulletin
Number 03-06-04-017A (Section 06 -- Engine/Propulsion System).


Important: The use of diesel fuel additives is not required or recommended
for the 6.5L diesel or the 6.6L Duramax® Diesel engine under normal
conditions. The filtering system is designed to block water and
contaminants without the use of additives. However, some customers may
desire to use fuel additives to improve the characteristics of available
diesel fuels.


Water Emulsifiers and Demulsifiers


If the customer desires to use a fuel additive, care must be taken in its
selection. There are two common methods that fuel additives use to cope
with water in the fuel. One method is through demulsification of water in
the fuel. This method causes water particles to combine together to form
larger particles, which drop out of suspension. This allows the fuel
filter/water separator to separate the water from the fuel as it is
designed to. The other method of coping with water in the fuel is through
emulsification. This method, often using alcohol as the emulsifier, keeps
water particles suspended in the fuel. Emulsification of water in the fuel
can allow water to get past the fuel filter/water separator, in most cases
causing damage to the fuel system. Only alcohol free water demulsifiers
should be used in General Motors diesel engines. GM Diesel Fuel Conditioner
®, P/N 88861009 (in Canada, 8886103 or both *Racor Power Shot Plus® and
*Stanadyne® diesel fuel additives are alcohol free and utilize water
demulsifiers to cope with water in the fuel. Other brands may be available
in different areas; be sure that they clearly state that they are alcohol
free demulsifiers before use.


*We believe these sources and their products to be reliable. General Motors
does not endorse, indicate any preference for or assume any responsibility
for the products from these firms or for any such items which may be
available from other sources.


Common Diesel Fuel Concerns


Fuel Waxing/Icing


Fuel distributors blend #1 and #2 diesel fuels for seasonal requirements in
a particular region. No other blending of fuels is recommended. However, a
customer may desire to use a winter fuel additive to prevent fuel waxing or
icing during extreme cold snaps. If a winter fuel additive is to be used,
it should not contain alcohol or other water emulsifiers that may
compromise the water removal effectiveness of the fuel filtering system.


Bacteria and Fungi Growth


Bacteria and fungi growth can occur in diesel fuel when there is water
present, especially during warmer weather. The best prevention against
bacteria and fungi growth is to use clean fuel that is free of water. There
are diesel fuel biocides available that are designed to kill bacterial
growth in the fuel system. However, the dead bacteria can still cause
blockages throughout the fuel system. If bacterial growth is found in the
fuel system, the proper method of removal is to flush the fuel system using
Service Manual procedures, replace the fuel filter element and refill the
tank with clean diesel fuel. If a customer desires to use a biocide after
flushing the fuel system, it should not contain alcohol or other water
emulsifiers.


Low Cetane Number


The cetane number is one indicator of a diesel fuel's ability to ignite.
There are many indicators of overall fuel quality such as cleanliness,
specific gravity, volatility, viscosity, detergency, corrosion inhibiting
abilities, and lubricity. Increasing the cetane number alone is not a fix
for poor quality fuel. Additionally, increasing the cetane number beyond
the engine's requirements will not increase performance. However, the
cetane number of diesel fuel is not always consistent and some customers
may desire to use a cetane improver to ensure full performance of their
engine. If such an additive is to be used, it must not contain alcohol or
other water emulsifiers.


Poor Lubricity


The 6.5L diesel and the 6.6L Duramax® Diesel engines are designed to
operate on today's low sulfur fuel without the use of additives. A fuel
additive designed to increase lubricity is not a fix for poor quality or
contaminated fuel, but some customers may desire to use a lubricity
additive to aid in the longevity of their fuel system components. If such
an additive is to be used, it must not contain alcohol or other water
emulsifiers.


Fuel Source Issue


If a vehicle is properly maintained but has fuel contamination issues,
consider obtaining fuel from a different source. Purchasing fuel from a
high volume fuel retailer increases the chance that the fuel is fresh and
of good quality.


|---------------------------+---------------------------------------------|
| Part Number | Description |
|---------------------------+---------------------------------------------|
| 88861009 | Conditioner, Diesel Fuel 325 ml (11 oz) |
| | |
| | |
| (in Canada, 8886103 | |
|---------------------------+---------------------------------------------|

Rattlehead - REALLY great info - Thanks! -- Lee

Fuel Additives

Rattlehead said:

This is a bulletin from GM on fuel additives. Whatever you use, just be sure it doesn't have any emulsifiers in it, such as alcohol, which suspend water in the fuel and therefore bypass the operation of a typical water separator. GM finally released their own fuel conditioner, which I believe is made by Racor, but there are other brands which don't use emulsifiers.

Click to expand...

Hmmm..the additive specified by the military (my post above) does contain an alcohol.
So does unwashed biodiesel, which contains a percentage of methanol.
I understood that the alcohol picked up the water and bypassed the water separator and finally burned as diluted alcohol without harming the engine because the water wouldn't arrive at the injectors as separate water droplets.

Racecar fuel, which is methanol is never 100%, it always contains a fraction of a % of water.

I also wonder how effective a water separator actually is, if it is not 100% effective, some water will pass and then arrive as separate water droplets, which will harm the injectors as the water turns to steam at explosive rate. I'd rather see some diluted alcohol then a percentage of free water.
Racor makes some pretty sophisticated water separators, but if they are not 100% effective, then what?

Wonder how much is a selling ploy by GM to push their own additive...

Need an independent expert's opinion here. Anybody here experienced with this chemistry?

Bjorn, good points. I can say that this bulletin was originally written before GM's release of the fuel additive, and they still held the position that no additives were advised. The reason for the bulletin was that it was known that customers were using additives even though GM did not condone the use of them. It was decided that, If customers will use additives anyway, they should at least be educated on what types are good or bad. Eventually, there was enough outcry from the field that GM should make an approved additive available, so they released their own and updated the bulletin with the part number.

One thing to consider is that water separation is more critical on a modern common rail design because of the high injection pressures. At full "throttle", they are running upwards of 26,000 psi. I don't think our low tech beasts are as vulnerable, but I still wouldn't want to pass water through the system, if at all avoidable.

When I imported my Toyota truck from Japan, I put a bottle of Slick50 diesel injector cleaner in. I drove the truck for about 10 miles before I got to a fuel station. My mate was following me in his car. After I put the cleaner in he said there was masses of black smoke coming from the exhaust, especially when i gave it some stick. I put another 2 bottles in at the next two fill ups (£14 per bottle). I got him to follow me on the third occasion and I really booted it hard. He said it hardly smoked at all.

So I guess it must work. A few weeks ago, I put a bottle of Redex diesel injector cleaner in. It's supposed to treat 8 tanks worth, I added the lot in one go. The truck went like sh*t off a shovel. Instant pick up and she got up there a lot quicker. The truck has a 3.0lt Turbo Diesel 3KZ engine.

Put plenty in. It workes for me.

I run powerservice in all 3 of my diesel engines,and the 3 previous ones and am happy with the results. Never jelled and no problems with dirty injectors. That said, there are new e.p.a. standards coming soon to remove most of the sulfer, and one other chemical I can't think of that add lubricity to diesel, so we're all gonna have to get used to using additives. And yes I do run power service year around, just at a lower concentration in the summer.

Katch1 said:

I run powerservice in all 3 of my diesel engines,and the 3 previous ones and am happy with the results. Never jelled and no problems with dirty injectors. That said, there are new e.p.a. standards coming soon to remove most of the sulfer, and one other chemical I can't think of that add lubricity to diesel, so we're all gonna have to get used to using additives. And yes I do run power service year around, just at a lower concentration in the summer.

Click to expand...

In the UK, we have had to use cra**y diesel for years now. They call it "ULS diesel" (Ultra Low Sulfer) or "city diesel". It doesn't smell like diesel, more like polish. It doesn't have as much "GO" as the old diesel and it smokes a lot less.

What damage this does to my engines I haven't got a clue. But what can you do when that's the only fuel available?

Add some homemade biodiesel, 5% or so.
Helps with the lubricity part at least.
Or how about a few liters of veggie oil added when you do a fill-up.

bio-diesel would definately help, m35a2, but there must be some sort of additive available on the shelf if you can't get your hands on any bio. I believe we start implementing the new standards next year.

I put an additive in my deuce and forgot to mix it. The engine ran smooth for a while then settled back down to the way it has always been

Some of the guys on my Toyota Hilux Forum are running veg oil in their trucks.

In the UK, you have to tell HM Customs and Excise that you want to use BIO diesel. You have to register as a fuel producer. Then, every month, you have to declare how much you use, and they send you a bill (duty).

The goverment talks big on being green, but they would loose too much money if they went the BIO Diesel route, as they can't be seen to tax the green option like they do normal fuel. So, Customs make it as hard as possible for anyone to register as a fuel producer.

Then there is different rates due, whether you mix the bio in the tank of the vehicle, or outside.

Basically, for every litre of Veg Oil, the goverment charges 0.43 pence per litre. So add the cost of the Veg oil and the Duty you get charged on the Bio, and it works out the same, if not dearer than normal Diesel.

There are people that don't tell customs that are running 50% diesel and 50% Veg oil (sunflower oil, or more common Rapeseed Oil). But if you get caught, your vehicle will be confiscated and you would have to pay LOTS of money in back duty.

I've run my Toyota Hilux Surf on 12lts of veg oil and the rest diesel, and it run perfectly.

What do you guys run for Bio diesel?

Katch1 said:

bio-diesel would definately help, m35a2, but there must be some sort of additive available on the shelf if you can't get your hands on any bio. I believe we start implementing the new standards next year.

Click to expand...

Would using Veggie Oil,

A) Alter or destroy any rubber seals in the diesel system?

B) Destroy the F.I.P?

C) Leave a sticky residue in the fuel tank/pipes etc

D) Does it burn off cleanly, or would it carbon up the head and foul the injector nozzels?

I love Marvel Mystery oil. Its good for your injectors and your top-end, and with all that particulate limitations on fuel, they need what they can get.

I have read elsewhere on this forum tha, in the US, today's low-sulfur diesel is not the best for our old FI pumps that depended on high sulfur levels for pump lubrication.

If this is true, it would seem that a lubricity additive might be indicated.

Somewhere else again on the forum, I read that from some study, MMO and WMO did not really do anything to increase lubricity. While that sounds surprising and against common reason, I wonder if it is true.

I wonder what the best lubricity additive is. The PO of my Deuce swore by FPPF Deluxe Total Power as an overall conditioner to the point of giving me several bottles with the truck, and asking me to promise to keep using it.