The 10 Best Diesel Additives

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This wiki has been updated 33 times since it was first published in April of 2015. If you want to prolong the life of your diesel-powered vehicle, you'll want to consider these fuel additives. The options on this list can protect against corrosion; prevent bacterial, microbial, and yeast growth; and help to lubricate engine components, leading to higher compression ratios for greater efficiency and power. We've made sure to include choices for cars and trucks, as well as boats. When users buy our independently chosen editorial picks, we may earn commissions to help fund the Wiki.

1. Stanadyne Performance Formula

2. Power Service 03080-06

3. Opti-Lube XPD Improver

Editor's Notes

March 15, 2021:

We haven't altered our rankings of diesel fuel additives recently, because many of these have been around for quite some time, and are all still excellent choices. If you're only using it periodically, Sta-Bil Stabilizer is a familiar and reliable choice that doesn't make any ridiculous claims, but simply works well. Alternatively, if you need to treat a few vehicles, the professional-grade Stanadyne Performance Formula four-pac can help you do so at a reasonable cost. Others, like Lucas LUC10013, are suitable for both gasoline and diesel engines.

All told, make sure that the one you choose is geared toward your specific issue, because there's a variety of formulations that can all accomplish slightly different goals.

May 10, 2019:

There is no question that diesel systems offer a number of advantages of their gasoline brethren, such as better towing capabilities, improved miles per gallon, and longer engine life. Unfortunately, they also have their fair share of drawbacks, like the tendency to be louder, rougher, dirtier, and release more emissions. They can also cost a lot to fix when regular maintenance is ignored. That's where these diesel additives come into the picture. They can smooth rough idling, reduce emissions, lubricate the fuel system, minimize the build up of sludge, and more, ensuring your diesel engine stays in tip-top shape for years to come. Whether you live in a hot climate or a cold one, Stanadyne Performance Formula is a suitable option that has been a top choice of professional mechanics for years, so you definitely can't go wrong with it. If you notice your ride has been idling a little rough lately, we recommend Opti-Lube XPD Improver or Power Service 03080-06. If your goal is to minimize smoking and engine emissions, you'll want to consider Lucas LUC10013, Red Line 85 Plus, Rev-X Distance+Boost. On the other hand, if the elimination of sludge and algae buildup is a top priority, we recommend Sta-Bil Stabilizer and Hot Shots Secret Extreme Clean & Boost, both of which can reduce water in the system. For marine engines, Lucas LUC10013 and Hammonds Biobor JF are the best options.

4. Red Line 85 Plus

5. Lucas LUC10013

6. Sta-Bil Stabilizer

7. Rev-X Distance+Boost

8. Hot Shots Secret Extreme Clean & Boost

9. Liqui Moly 2002 Super

10. Hammonds Biobor JF

Why You Need Additives

Diesel is thicker and oilier than highly refined, regular gasoline, and for this reason it’s more prone to having its properties change over time.

After bringing your car into a body shop for a full inspection and tune up, your mechanic may come to you with a list of things you can do at home, between visits, to keep your vehicle running smoothly. One thing that will probably be on that list is the use of a fuel additive.

Most car owners ignore this advice, but if you use diesel fuel it’s especially important that you listen to your mechanic. Diesel is thicker and oilier than highly refined, regular gasoline, and for this reason it’s more prone to having its properties change over time. Another reason diesel fuel is sensitive to change is that it’s usually stored for long periods of time, whereas regular gasoline typically burns off much more quickly.

Fuel additives – whether for diesel or regular gasoline – improve the quality and efficiency of your fuel. Some additives boost the octane level in your fuel, making less go a long way. This means you don’t have to fill up as often, which can save you money. Other additives focus on engine maintenance by preventing the accumulation of deposits. When sludge and other contaminants build up in your engine, it has to work harder to function, and that can shorten the life of your car.

Cold flow improvers are especially important for diesel fuel if you store it in the winter because it gels up under cold temperatures. A cold flow improver prevents this from happening and preserves your fuel for later use. Diesel Exhaust Fluid is another product that anybody driving a diesel car should know about. DEF goes into the diesel exhaust gas stream and breaks up nitrogen-oxygen compounds. When DEF is low, a car might slow down to as little as five miles per hour.

How Diesel And Gasoline Differ

Diesel and gasoline both start out as crude oil that’s been pulled from the earth, but once they’re separated at refineries, they go through different processes.

Diesel and gasoline both start out as crude oil that’s been pulled from the earth, but once they’re separated at refineries, they go through different processes.

Gasoline and diesel engines are both internal combustion engines, meaning they both convert fuel into energy through a series of tiny explosions. It’s how these explosions occur that makes the two fuels different, and also what makes diesel more efficient. In a gasoline engine, the combustion is spurred on by spark plugs; in a diesel engine, air is compressed first and then fuel is injected. Since air heats up when it’s compressed, the fuel ignites when it enters. Diesel also has a lower autoignition temperature than gasoline does, so it ignites quicker.

Both diesel and gasoline engines use a four-stroke combustion cycle. The first stroke takes place when the intake valve opens, which allows air to enter the chamber, that in turn causes the piston to go down. The second stroke initiates when the piston moves back up and compresses the air. When the piston reaches the top, fuel injects into the combustion chamber and sends the piston back down to create exhaust; that's the third stroke. The final stroke sends out that created exhaust. That's what happens when you start a car.

The difference between diesel and gasoline engines is that one uses spark plugs to ignite the fuel, and the other only requires a heat source.

Recent Improvements In Diesel Products

Cars that produce a lot of exhaust are usually blamed for creating high levels of smog in cities, and those cars are often diesel engine vehicles. But diesel cars have come a long way since their popularity during the 1970s fuel crisis. When diesel cars first premiered, consumers were displeased by their noisy engines, and put off by the amount of black particles that can emit out of the exhaust pipe. This left diesel cars with a bad reputation that they’re still recovering from, but with the advancements of fuel additives, they have become more well-received in recent years.

Ultimately, the proper use of additives can help these improvements do their job, since they’re designed with a well-maintained diesel engine in mind.

In the last two decades, the government has required that the manufacturers of diesel engines include emissions control equipment that keeps pollutants from entering the atmosphere. Most newer diesel engines have filters that trap and contain the black smoke you used to see swirling around cars. Some models have catalytic converters that burn soot as it's made, reducing carbon monoxide and hydrocarbons by nearly 90 percent.

Diesel fuel now is better refined and made with fewer dangerous emissions, and diesel engines are changing to work in conjunction with cleaner fuel. There are even advanced computers that monitor fuel combustion in injection devices to further reduce emissions. Ultimately, the proper use of additives can help these improvements do their job, since they’re designed with a well-maintained diesel engine in mind.

Christopher Thomas
Last updated by Christopher Thomas

Building PCs, remodeling, and cooking since he was young, quasi-renowned trumpeter Christopher Thomas traveled the USA performing at and organizing shows from an early age. His work experiences led him to open a catering company, eventually becoming a sous chef in several fine LA restaurants. He enjoys all sorts of barely necessary gadgets, specialty computing, cutting-edge video games, and modern social policy. He has given talks on debunking pseudoscience, the Dunning-Kruger effect, culinary technique, and traveling. After two decades of product and market research, Chris has a keen sense of what people want to know and how to explain it clearly. He delights in parsing complex subjects for anyone who will listen -- because teaching is the best way to ensure that you understand things yourself.

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