Diesel vehicles enjoy higher fuel economy, longer engine life, as well as unmatched reliability. This is large in part because of the fuel itself as well as diesel fuel additives.
Diesel fuel additives are somewhat of a controversial topic. Which diesel fuel additive you should use, as well as whether these additives even work often comes into question.
There's no denying that today's low-sulfur diesel is better for the environment. However, it comes at the cost of lubrication that your diesel engine needs. That's where fuel additives can help.
Choosing the right diesel fuel additive for your vehicle isn’t always straightforward. These fuel additives don’t have any specifications you can look at, and often there are different types for various functions.
The Best Diesel Additive
1. Stanadyne Performance Formula One Shot Additive
Few brands in the fuel additive industry boast the credentials that Stanadyne does. For 65 years they've manufactured fuel injection equipment for diesel engines. As you might expect their fuel additives are engineered to work.
Stanadyne notes that the Formula Performance one-shot is designed to tackle virtually any diesel fuel related issues including anti-gelling, corrosion prevention, and lubrication.
Stanadyne also notes improved performance, horsepower, and fuel economy. However these metrics are hard to gauge and not everyone should expect
The Formula Performance one-shot is also approved by several original equipment manufacturers (OEMs) like Ford, GM, Deere and Navistar.
Each bottle can treat up to 30 gallons of diesel fuel.
2. Power Service Diesel Fuel Additive
It wasn’t easy choosing between this and our overall pick. Sadly, the Power Service diesel fuel additive came in second. But don’t be fooled, there is a lot to like about this product. It may even be the one for you if you’re on a budget.
Once again, Power Service has come out with the most affordable diesel fuel additive on the market. Sold in cases of twelve 32 oz bottles, what you have here is a true bargain. A case is likely to last you for well over a year. There really isn’t a better deal you can find for additives.
Performance-wise, we’re happy to report that this diesel fuel additive by Power Service delivers in every way you would expect it to. If you’re looking to improve your vehicle’s fuel economy, keep your injectors clean and your diesel fuel well-lubricated.
It also provides a significant cetane boost. If you drive a European car and use US diesel, that cetane boost may even be necessary for your vehicle to run well. Power Service truly outdid themselves with this product.
3. Lucas Diesel Fuel Treatment
While it isn’t the most affordable option on the market, the Lucas Oil Fuel Treatment still delivers on most of its promises. Lucas Oil will improve your vehicle’s mileage, clean and lubricate your vehicle’s fuel system, and increase its longevity by ensuring that your injection pump and injectors are kept clean.
As a result, you won’t have to worry about replacing your injectors anytime soon. That can save you a lot of trouble and money down the road, which is enough to justify the price tag.
Lucas also claims that its diesel fuel additive will improve your vehicle’s fuel economy and mileage. However, this can vary based on the driver. If you drive on the highway/freeway a lot, you may notice more of an improvement to your fuel economy.
4. Liqui Moly Super Diesel Additive
Liqui Moly’s Super Diesel Additive does most of what it promises to do. It’s fairly affordable and outperforms its low price tag. For that, Liqui Moly definitely deserves praise. It isn’t the first product we’d recommend, but if you’re on a tight budget, this additive may just do the trick for you.
This additive will lubricate your vehicle’s diesel fuel (and by extension, your vehicle’s fuel pump) like very few others. US diesel tends to be plagued by a lack of lubricity, which can seriously affect the longevity of your fuel system. However, Liqui Moly’s additive is able to make up for that.
Sadly, you probably won’t notice a lot of improvement to your vehicle’s horsepower or mileage. But for protecting your vehicle’s most important components, this additive works better than expected. Liqui Moly has done a great job with this product.
5. Howes Diesel Additive
If you live in an area where the weather is especially cold, this diesel fuel conditioner and anti-gel mixture from Howes can save your car’s engine.
Fuel gelling is a common problem that diesel owners have to deal with. If harsh weather conditions are a common occurrence where you live, fuel gelling can seriously impact your ability to drive, especially in the winter and fall. Needless to say, with how many of us commute to work, gelled fuel can severely impact your livelihood as well.
Thankfully, Howes offers an affordable solution that is safe and effective in all diesel and biodiesel blends up to B-21, customers have so far reported zero problems with gelled fuel in the winter while using this product.
What are Diesel Fuel Additives?
Diesel fuel additives are various chemicals that can be added to diesel fuel. These chemicals can have a variety of functions. In general, additives are meant to increase the lubricity of fuel, prevent it from “gelling” in harsh, cold weather, and to keep various vehicle components clean.
What fuel additives are most useful for is lubricating your vehicle’s fuel, preventing gelled fuel, cleaning injectors and other components and reducing carbon dioxide emissions.
Added horsepower, improved mileage or fuel economy are bonuses, but not what diesel fuel additives are generally meant for.
Types of Fuel Additives
When you are choosing a fuel additive to use with your diesel engine, one of the biggest things that you need to take into consideration is what type of additive you use. At the time of writing, there were four common kind of fuel additives for diesel engines.
It's rather normal for diesel's quality to diminish over time due to either degradation or oxidation. Fuel stabilizers are designed to improve the quality of the diesel which prevents breakdown, degradation, and oxidation.
These types of fuel additives are the responsible for improvements in fuel combustion as well as the reduction of ignition delay. When the cetane boost is high, the better the efficiency of the engine.
Aside from improvements in engine performance, you can also count on cetane boosters to cut off smoke emissions, prevent deposits, and slow down the consumption of fuel.
Fuel Injector Detergents
As with any other organic substance, it's possible for diesel to accumulate mold, yields, and bacteria, among many other deposits. Fuel injector detergents are able to clean up any unwanted dirt which might be blocking up the injector nozzle of your vehicle.
Additionally, detergents like these are also able to clean many other engine parts which get exposed to diesel. After this, you should expect improvements in both hard start and acceleration.
Even though any water that is found in diesel can be useful for both fuel temperature stabilization and condensation, the dissolved salt might result in crystallization that eventually leads to things like corrosion and rust. Having said this, corrosion inhibitors play a big role in the interception of crystallized salt in order to prevent that rust or corrosion. Typically, many corrosion inhibitors will contain alloy or metal chemical compounds.
If you live in a really cold area, then the diesel fuel filter can wind up getting blocked thanks to the accumulation of gel or wax formation in the diesel. Anti-gel additives are used to prevent the viscous effect inside diesel during any cold weather so that cold-starting performance is improved. Also, anti-gel additives might unblock diesel fuel filters.
The benefits of diesel fuel additives vary from product to product. Many manufacturers claim that their additives can increase your vehicle’s horsepower and improve your mileage and fuel economy. With that said, these claims don’t always come to fruition.
Diesel fuel additives are sometimes meant for specific vehicles. For example, nitromethane-based diesel fuels are typically meant to be used in race cars. However, most aftermarket diesel fuel additives are meant for average cars.
Why are Fuel Conditioners Necessary
Fuel additives weren’t as common or necessary in the past. But, the fact of the matter is, they’re absolutely necessary for this day and age. The reason for that is, in short, fuel today just isn’t what it used to be.
Nowadays, fuel refiners are under a lot of pressure to reduce sulfur content in order to meet new emissions-control standards. While that’s meant to help protect the environment, a side-effect is that the quality of distillate fuels today is notably lower. Fuels have more undesirable elements and aren’t as stable.
One way in which diesel suffers today is lubricity. As mentioned above, refiners are under a lot of pressure to lower sulfur content. The most cost-effective way of removing sulfur is through hydroprocessing, a process in which sulfur is removed and replaced with hydrogen. A side-effect of this process, however, is that the hydrogen tends to react with and remove the compounds that provide diesel with adequate lubricity.
Because your vehicle’s fuel system partly relies on diesel fuel to stay lubricated, a lack of lubricity can lead to severe damage over time. Namely, it can result in wear and scarring between unlubricated metal parts, shortening the life of vital components.
That’s why one of the uses of aftermarket fuel additives is to keep your vehicle’s fuel lubricated, thus making up for its lack of natural lubricity.
Diesel Fuel Additives and Gelling
Another important reason for using additives is to prevent “fuel gelling.” Diesel has what is called a “gel point.” The gel point of diesel fuel is the temperature at which diesel or biodiesel will freeze. Once frozen, it can no longer be pumped through your vehicle’s fuel lines. Anti-gel additives prevent gelling by stopping paraffin wax crystals from forming.
Lastly, additives can reduce your vehicle’s carbon dioxide emissions. Diesel-powered vehicles are widely known for the negative effects they have on the environment. Additives can help alleviate that, to a degree.
In the video below Scotty Kilmer talks about reasons for using additives, including the Liqui Moly we mentioned above.
Sadly, choosing a fuel additive isn’t a straightforward process. However, we hope you’ve realized just how important diesel fuel additives are. With a bit of trial and error, you should be able to find the product that works best for your vehicle.
The main thing to consider is the type of fuel additive and the goal you're trying to accomplish with your vehicle.