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Do You Need Diesel Additive?

If you decide to use an additive in a farm diesel, make sure you understand what it can do and what your engine needs. Don’t just pour in any old additive as a matter of routine.

Whether to use an additive in diesel fuel is one of those topics that sparks a variety of opinions among farmers. It sparks debate among those in the machinery industry as well.

Louis Wenzler, a market communications director for Cummins, says Cummins, like most other engine manufacturers, does not recommend the use of fuel additives. The company’s official position is that operators should ensure they are using a fuel that meets the proper specifications. Typically that means a No. 2 diesel that meets API specifications. Having said that, Cummins does recognize that under certain situations an additive may be useful to counter certain specific fuel problems.

Some of the things Cummins’ service bulletin recognizes that additives could correct are the formation of fungus inside fuel tanks during long-term storage or increasing the lubricity of diesel. It also says additives can be used to prevent gelling of fuel in extremely cold weather or icing of fuel lines, but Wenzler points out that fuel should not be contaminated with water that would lead to winter icing problems in the first place. And under some circumstances, it may be necessary to add a cetane booster if the commercially available fuel doesn’t meet the necessary standard.

“One thing that is a problem in Canada is cetane level,” says Percy Hoff, CEO and president of DSG, a fuel additive provider. The cetane rating in diesel is the equivalent of an octane rating in gasoline.

But petroleum manufacturers say if you are buying fuel from a major company, you shouldn’t need to use additives to get your diesel up to the standard required by engine builders. “If you’re using diesel fuel that meets specifications, you should not need to put any additives into it,” says John Skowronski, director of environmental affairs at the Canadian Petroleum Products Institute (CPPI). “The simple view is the products (diesel fuel) on the market from CPPI members [already] meet specifications,” he says.

However, reduced engine deposits may be the primary benefit of using an additive on a regular basis. “The biggest [reason] is detergency,” says Hoff. With the reduced sulphur levels in today’s low and ultra-low sulphur fuels and the higher injector pressures used in modern engines, a problem called thermal destabilization can occur.

In a 1980s model (engine), injection pressure would have been around 22,000 PSI. Now, it’s at 40,000 PSI and more,” Hoff says. As diesel moves through the engine’s high-pressure fuel system, some of it is returned to the tank, unused. That results in it being heated and cooled repeatedly, which causes thermal destabilization. The by-product of that is increased engine deposits and shortened fuel filter life. Hoff says a quality fuel additive, such as the one his company produces, can significantly reduce that problem.

As well, it seems at least some petroleum companies, who also make fuel additive base chemicals, recognize there are benefits in going beyond just meeting engine manufacturers’ required fuel standard. At the Chevron corporate web-site, under “fuel additives,” you will find this quote: “Aftermarket additives are an excellent choice for preventative maintenance and as a precaution against fuel-related problems. These additives may improve the performance from your gasoline or diesel fuel.” And it’s that preventative maintenance aspect that may be the real value offered by additives.


Fuel additives are not created equal, Hoff cautions. “Be aware of the snake oil that’s out there,” he says. “Some of the cheaper ones can actually harm your engine.” Additives on the market all contain varying amounts of several different base chemicals. The exact blends are usually proprietary secret, but the particular chemicals used and their concentrations are what set the various additives apart. The base chemicals selected for a blend depend on what specific fuel problem the additive is meant to correct.

Hoff warns that some chemicals in cheaper products may not even be compatible with all the components in injector pumps and can cause damage. He says he has seen severe damage to fuel systems caused by poor additives, and suggests asking a manufacturer for a compatibility report if you have any doubts. Failing that, make sure you read the label.

He recommends you look for something that meets a manufacturer’s specifications and industry standards. “A poor additive will not advertise those [standards], because they’re not able to.”

Getting all the information you need to make an informed purchase may mean doing some research. The Internet can be a useful tool, according to Hoff. Also, check the information provided by the manufacturer of the engine you’re using.

“Most cheap additives use three to five per cent active ingredient,” says Hoff. “The rest is solvent. With a good product, the active ingredient is 75 per cent.”

To determine an additive’s value, Hoff recommends checking the label to see how much fuel an additive can treat rather than considering the size of the container. And the type and quality of solvent used also affects how well the additive disperses within the fuel tank.

The colour of an additive will tell you about its concentration. “The secret is to look at the colour. When you see a darker colour, you know you’re getting a good [highly-concentrated] product,” he says.

Hoff agrees with Chevron that good quality additives can pay dividends. “If you use a moderately-priced fuel additive, it will pay for itself,” he says. And to back up that claim, he points to the use of his product by the Alberta Motor Association’s tow truck fleet in Edmonton, which has since seen a reduction in their regular engine maintenance costs since it starting using the DSG additive.


Dave Pyke, operations coordinator at the Alberta Motor Association, was involved with the decision to go with additives in the tow truck fleet. He confirms the organization has seen significant cost savings as a result. In the 40 diesel-powered Ford trucks it uses, AMA had been frequently

changing injectors. “We had been, on average, replacing a eight-pack of injectors [in each truck] every 18 months,” he says. Now only a handful of injectors are replaced in the entire fleet each year. Pyke says replacing a full set of injectors cost the operation about $4,000 per truck. Eliminating that expense has produced significant savings.

To achieve these results, drivers operating 2007 and older Ford trucks using the Navistar engines added a small amount of additive at each fill. Every 30,000 kilometres, the trucks received a special injector cleaning. In their newer Dodge trucks using Cummins engines, AMA is just using a cleaning agent added directly to the fuel.

Pyke says farmers should seriously consider using an additive with detergent capabilities in farm engines. That, he says, could reduce injector servicing costs, particularly as low-sulphur fuel becomes mandated for off-highway use. But, like Hoff, he cautions that producers need to do their homework before using any fuel additive. Some additives cannot be used with newer diesels that have particulate filters to reduce emissions, particularly in late-model pick ups. “Old-style fuel additives should not be used with newer engines,” he says.

The lesson from all this seems to be that if you decide to use an additive in the farm diesel, make sure you understand what it can do and what your engine needs. Don’t just pour in any old additive as a matter of routine. Select one that has the properties needed to make the right kind of improvement. And be sure you are an informed consumer. Don’t put an expensive engine at risk by going cheap on an additive that may do more harm than good.

Scott Garvey specializes in writing about tractors and farm machinery technology for publications in Canada and Great Britain. He’s also a former affiliate member of the Society of Automotive Engineers (SAE). He farms near Moosomin, Sask.

About the author


Scott Garvey

Scott Garvey is a freelance writer and video producer. He is also the former machinery editor at Grainews.

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