In this Guide
Diesel can be a fickle fuel, that’s for sure! Whether it’s gelling at cold temperatures, or impurities from your fuel source, or moisture in your tank, there are lots of issues that can impair diesel motors.
Diesel additives do a number of different things to compensate for the disadvantages of diesel. They stabilize it, helping it burn smoother and cooler. They also eliminate moisture, and add lubrication.
There are all sorts of additives on the market. Each of them serves a different purpose, and suits a specific fuel or vehicle. Problem is, it can be hard for consumers to figure out which additives are worth the money, and which are just expensive snake oil. That’s where we come in!
We’ve created this handy guide to the best diesel fuel additives. It’s designed to help you find your ideal solution quickly and easily, so you can get off the computer and back on the road.
We’ve selected 6 of our favorites to show you! They suit a range of fuels and vehicles, as well as driving styles and individual needs. We chose them based on their effectiveness, versatility, and overall value.
Let’s start by taking a quick look at some of our favorites:
|3.||Howes Diesel Treat|
Diesel Additive Reviews
1. Liqui Moly
“our top quality recommendation.”
Liqui Moly is a German additive that’s currently our top quality recommendation. It’s very popular with Audi, Volkswagen, and BMW customers, which are the most common diesel passenger brands on the market right now.
We love that it comes in convenient quantities for tanks, and is an all-around improver for your diesel. We highly recommend it for technical, modern diesel systems, as well as drivers of older vehicles who simply want the best solution out there.
It has plenty of detergents to keep injectors and other engine components clean. That means smoother startups and idle, as well as fewer restarted cycles. You’ll also improve the power and performance of your car, since more fuel will be hitting the firing chamber.
It’s compatible with turbo-chargers, and is tested to improve performance with turbo-charged systems. That’s a big plus if you drive a European car, many of which have turbochargers built in. It’s also specially formulated to be safe for direct-injection systems. Many other solutions are not!
“works with any type of diesel, and suits just about any type of motor.”
It works with any type of diesel, and suits just about any type of motor. While it tends to be a favorite of car drivers, we’ve found that the few American construction or trucking workers who know about it swear by it.
It helps preserve engines, especially during long periods of disuse. That’s thanks to the range of lubricants that are integrated into the solution. They also help to prevent knocks and seizing.
Speaking of lubricants, this stuff really improves the cetane rating of your fuel. It’s especially important for those newer, more technical diesel injectors. They can wear out and develop problems very quickly if you run them on straight low-sulfur diesel.
“this stuff really improves the cetane rating of your fuel.”
It’s designed by Europeans, who have a very different standard. Their diesels have much better lubricity and stability, and their motors are designed to work with that standard. This solution helps American diesel sources come up to par.
Even if you don’t have a finely tuned German engine, your motor will run much more smoothly with this stuff in the line. We’re very impressed by Liqui Moly, and we’ve found that other reviewers quickly became loyal customers for life.
We found that fuel economy increased noticeably after using Liqui Moly. We found that on average, you’ll see about a 3-5mpg difference, which levels out to around 10%. In many cases, the Liqui Moly pays for itself in savings.
It’s made in Germany, so you can expect a much better standard of quality control than with the American brands that make their additives in China. German design also means that this stuff is much more environmentally-sound than some of the alternatives.
“this stuff is much more environmentally-sound than some of the alternatives.”
It’s conveniently sized for each tank of fuel. The 300 ml cans are small enough to store easily around the car, and super easy to empty with each fill-up. No lugging around gallon jugs, or trying to judge how much to use. You simply use one can per tank.
The antioxidants in the solution prevent corrosion, and help break down water molecules. If water is a frequent issue for you, it won’t be with this one!
It’s extremely inexpensive. You wouldn’t think that the premium German solution would be one of the cheapest, but somehow it is! This actually one of the least expensive of our recommendations by the ounce.
Some users writing online said they didn’t notice much of a difference. If you’re driving a newer vehicle, and use the appropriate premium fuel, you might not need this one.
For the rest of us, the difference will probably be apparent. That’s particularly true if you use any sort of ethanol in your fuels, or if you run biodiesel. Plus, you’ll have to remember that not noticing anything drastic is probably a sign that your engine is running well. It’s worth keeping in mind that without the additive, you might be noticing something wrong.
2. Royal Purple
“a very popular choice among truck drivers and construction workers.”
This Royal Purple compound is a very popular choice among truck drivers and construction workers. It’s part of Royal Purple’s lineup of diesel oils and additives, most of which are best-sellers.
This particular solution is designed to be compatible with the latest direct injection motors, as well as older styles. We think it’s a great American alternative to the Liqui Moly.
It cleans all around inside your engine. This one is designed to keep injectors, carburetors, and combustion chambers free of soot and carbon deposits. It cleans old deposits and keeps new ones from forming.
It comes in a couple different sizes, so you can choose the dose that’s right for your tank. You can buy this in either 10 or 20 oz cans.
“It comes in a couple different sizes, so you can choose the dose that’s right for your tank”
Like the Liqui-Moly, the Royal Purple can help with your fuel economy. It’s especially effective at restoring lost fuel economy on older cars. That’s because it cleans out stifling deposits, and evens out fuel to make it burn more cleanly and smoothly.
It improves startup. We’ve noticed a difference in both hot and cold conditions. This solution prevents gelling, and the detergents mean fewer coughs and sputters as your motor gets going.
It’s specially designed to work with newer direct-injector systems, especially HPCR (high pressure common rail) systems. You’re safe to use this one on newer trucks and farm equipment, as well as European cars.
“It works with absolutely any type of diesel”
It works with absolutely any type of diesel, from #1 or #2 grade, to ethanol base, or biodiesel. It also works with particulate filters and catalytic converters, so you don’t have to worry about emissions tests or smog.
It really boosts your cetane number, by up to 8 points!
It’s not quite as concentrated as the Liqui Moly. You’ll need to use a bit more per tank of diesel.
It doesn’t pour quite as easily as the Liqui Moly, since the German product has a handy nozzle and the Royal Purple just has a cap. You’d be well-advised to keep a funnel handy when you start using this.
It’s harder to get by the case than Liqui-Moly. That can make the unit price a bit higher.
Some users didn’t notice as much of a boost in their fuel economy as they anticipated. Some drivers of older cars noticed that it helped, but drivers of newer cars said they were satisfied by the fact that their economy wasn’t on the decline.
“ideal for drivers who live in cold areas”
This Howes additive is a favorite among fleet managers and people with lots of diesel equipment, like farmers and town maintenance crews. It’s ideal for drivers who live in cold areas, as well as people who need a cost-effective solution for boosting the cetane/lubrication rating of their fuel.
It’s very inexpensive. This solution is even cheaper than Liqui Moly, and it’s one of the cheapest on the market. We also like that it comes in bigger quantities (half gallon bottles).
“one of the cheapest on the market.”
It works in all diesel blends, including low-sulfur and biodiesel. One previous buyer we heard from even said he used it in his mother’s oil furnace during cold winters, and saw great results with that too!
It’s a beast in cold conditions. This stuff is guaranteed to prevent gelling. That’s because it lowers the cold filter plugging point in your fuel line by 20 degrees!
Northern users swear by Howe’s, and said they had no problems starting up their engines even at sub-zero temperatures (F). If you live in a colder area, this one might be an essential additive. While some other products prevent gelling to some degree, this is the stuff the Northern plowmen swear by.
“If you live in a colder area, this one might be an essential additive.”
The added lubricity boosts your cetane rating big time. It makes a substantial difference in the smoothness of your engine, and cuts down on the likelihood of your fuel leaving deposits on your injectors or other engine components.
It eliminates water in your fuel, which is especially important in cold conditions. Water can freeze in filters, causing major issues. If you’re using Howe’s, you won’t have to worry about that.
While you’re less likely to have problems with fuel deposits from diesel treated with Howe’s, it’s not a cleaner. If you’ve got an older vehicle with deposits already built up, you’d be better off with one of the other options.
You may also find that you need to run some injector cleaner through the system every oil change or so, to make sure things are working as smoothly as possible.
We haven’t used this on newer systems ourselves, since it makes no bones about the fact that it’s designed for trucks and heavy equipment rather than a trim VW. We can’t say whether you’d run into problems using this on a more recent direct-injection engine, but it’s not designed with them in mind.
If you’re thinking about your injectors, you might have a look at this other Howe’s treatment, which is a good periodic injector cleaner.
“This stuff cleans, smooths out fuel, and improves the economy of all your motors–gasoline or diesel.”
The Lucas fuel treatment is one of the most popular on the market, period. We love it because it’s compatible with absolutely any fuel. It’s perfect for people who have several vehicles, even if they have different fuel types.
This stuff cleans, smooths out fuel, and improves the economy of all your motors–gasoline or diesel. Plus, the low cost makes it accessible for nearly any driver.
The blend of lubricated oils and added detergents helps your diesel engine run more smoothly. It also improves starting and firing reliability. You’ll see less wear on your engine components, since the Lucas blend compensates for low sulfur fuels. It also has detergents to keep fuel smooth and even.
It’s inexpensive. Plus, you get a whole gallon in each bottle. That makes it more convenient for bigger tanks.
It improves mileage, especially on older vehicles that have lost efficiency over time. While some other additives improve mileage as a side benefit, the Lucas treatment is specifically designed to save fuel.
“the Lucas treatment is specifically designed to save fuel.”
It keeps injectors clean, thanks to the detergents. You’ll keep both your injectors and your fuel pumps safe with the Lucas treatment. It’ll clean all the components in the fuel line.
Faithful users say it really cuts down on knocks and misfires. Since it does such a good job compensating for lower quality or inconsistent fuels, it’s an excellent solution for professional drivers who are often in different parts of the country where fuel might vary. And since it’s cheap, it’s very cost-effective for professional truckers.
“it’s an excellent solution for professional drivers who are often in different parts of the country where fuel might vary.”
It helps cut down on excess emissions by keeping fuel consistent. Smog is often caused by rough particulate matter and sludgy bits in diesel. The Lucas product helps break those lumps down so they can be burned more efficiently. It adds some detergent to the fuel, which keeps everything more consistent.
It increases lubricity to compensate for low-sulfur diesels. That helps your components stay free of wear and tear from poor fuels. This one also helps with the smog problems associated with low-sulfur fuels. The Lucas treatment will help you meet emissions standards easily. That can be especially important if you run biodiesel or use an older vehicle.
It’s one of the only fuel treatments that’ll work on both diesels and gasolines. That’s why we recommend the Lucas for drivers who have multiple vehicles, or lots of motor tools around the house (weedwhackers, lawn mowers, chainsaws). You get a lot of bang for your buck, and it’s the only product you’ll need to buy!
“one of the only fuel treatments that’ll work on both diesels and gasolines.”
It has a lot of the same benefits on gasolines, including improved fuel economy, added lubricity, and injector cleaning. We like it because it gives you lots of the benefits of leaded fuels without the dangerous lead content.
It’s made right here in the USA.
It’s not a super concentrated cleaner, so you really do have to use it at every tank in order to keep everything deposit-free. The Lucas treatment does clean injectors, but it’s better as a preventive measure. That’s why we recommend using it as an additive.
While many people buy this treatment in the hopes of increasing fuel economy, drivers of newer vehicles might not see much of a difference. That’s true for all these additives, but we think it’s important to point out since the Lucas is specifically marketed as an economy booster.
“combines the cold weather benefits of the Howes treatment with the cleaning power and fuel stabilizers of some of our other recommendations.”
This Stanadyne product isn’t as big a seller as the Lucas, but it has some of the most faithful users on the market. It’s a similar fuel treatment in that it’s an all-around performance booster, with a blend of detergents and lubricants.
The Stanadyne claims to be the “most comprehensive” diesel additive on the market, and we’re hard pressed to argue! It combines the cold weather benefits of the Howes treatment with the cleaning power and fuel stabilizers of some of our other recommendations.
It’s a favorite among VW drivers. Stanadyne injectors are used in most VW motors, and this solution is made by the same company. It’s compatible with all European cars, old and new. It’s also a good choice for newer, direct diesel injectors.
“a good choice for newer, direct diesel injectors.”
It’s almost as cheap as the Lucas. Since the Stanadyne is more concentrated, we think you get more bang for your buck. A half-gallon treats 250 gallons of fuel.
It comes in large quantities. This stuff is sold by the half-gallon, so you’re not paying for packaging. The shape of the jugs makes it super easy to pour into truck tanks.
It’s specially formulated for ultra-low-sulfur fuels. It provides added lubricity for your fuel, which helps preserve your motor components keep your injectors working smoothly.
It also cleans all around your fuel system, including your injectors and combustion chambers. As a result, this solution boosts your torque, horsepower, and acceleration.
“the Stanadyne Performance Formula is one of the only ones that’s tested to prove its worth.”
While nearly every diesel additive claims to improve your fuel economy, the Stanadyne Performance Formula is one of the only ones that’s tested to prove its worth. According to an independent lab, this stuff provides up to 9% gains in fuel economy, with an average boost of 4%.
Like our other recommendations, Stanadyne boosts your fuel’s cetane rating.
It’s tested to be compatible with all engine systems, and it’s designed to work with filters and smog controls after the engine. This solution also reduces particulate emissions, since its detergents break up any gunky bits in the fuel. That makes for a cleaner burn, and a clearer exhaust.
It’s one of the only additives that’s designed to prevent wear and tear on rubber seals, which is a major issue with low-sulfur diesels. As a result, you won’t have to replace O-rings in your injectors and other valves nearly as often.
“actually a bit more effective in cold conditions than the Howe treatment.”
It’s great for cold weather. The Stanadyne is actually a bit more effective in cold conditions than the Howe treatment. It’ll lower the cold plug filter point by 25 degrees F, and it improves pouring conditions by around 40 degrees F.
It reduces water content and prevents corrosion. It has special demulsifiers which cause water droplets to come out of suspension, so they can be evaporated.
It’s alcohol-free, so you don’t have to worry about corrosion on your components.
As with some of our other recommendations, one or two previous buyers whose reviews we read online were unimpressed with the results. However, they were driving newer vehicles, which as we’ve said don’t tend to show drastic improvements (since they’re less likely to have lost performance in the first place).
“outstanding lubricity and stabilizing properties.”
This Opti-Lube formula is a favorite among professional truckers. It’s an all-around treatment like the Stanadyne or Lucas, and it provides many of the same benefits. We like the Opti-Lube for its outstanding lubricity and stabilizing properties. Plus, its preservatives make it an excellent supplement for biodiesel makers and fleet managers with lots of fuel to keep stored.
According to an independent study, this one provides the best overall lubricity of all the major additives. It boosts the cetane rating of your fuel up to 3 points, and keeps even the latest direct diesel injection systems working smoothly.
“provides the best overall lubricity of all the major additives.”
It helps in cold conditions, allowing diesel fuels to flow at -10 degrees F. The Opti-Lube will also prevent gelling at cold temperatures down below zero. That’s comparable performance to the Howe and Stanadyne additives.
It includes detergents to keep your injectors and fuel line clear of buildup or deposits.
It prevents rust and corrosion by separating water molecules so they can be burned cleanly.
It’s an excellent stabilizer. This product doubles the storage life of most diesels, so it’s a good choice for people who make their own biodiesel fuel. It’s our top recommendation for people who store lots of fuel around their property or business location.
“It’s our top recommendation for people who store lots of fuel around their property or business location.”
It’s compatible with all emissions systems. The detergents actually lower smog, and the solution doesn’t interfere with post-motor filtration systems.
Since it comes by the gallon, it’s a good choice for truckers who will be on the road for long trips. It’s also an excellent size for treating big tanks on farm equipment or larger trucks.
It’s pretty expensive, especially compared to the Lucas or Stanadyne (which provide most of the same benefits).
As with most of our other recommendations, we found a few naysayers who didn’t notice quite the improvements they were hoping for.
Which is the Best Diesel Additive for You?
Liqui Moly is the best choice for people with newer cars, especially European diesels.
It’s specially formulated to compensate for the poor quality of American fuels, and it’s compatible with newer, more technical diesel injector systems. Even though it’s not a popular additive among more industrial drivers in the States, we’re hard pressed to see why. It’s affordable, effective, and very easy to use.
We’d recommend it for any diesel motor, but the size makes it a perfect dose for passenger car and truck tanks. It’s our overall top quality choice!
The Royal Purple solution has many of the same benefits as the Liqui-Moly.
It’s much more popular here in the USA, and even though we don’t think it’s necessarily better, it has a massive following among professional truckers. We like it for the big cetane boost it provides to fuels.
However, it’s slightly more expensive, and a bit more awkward to dispense than Liqui-Moly. Essentially, it’s a solid American alternative for people with newer diesel motors.
Howes is our top choice for people whose primary goal is to make diesel work in cold conditions.
While it’s not the most powerful detergent of our choices, it provides the most comprehensive cold-weather protection. It’s also pretty cheap, which makes it affordable for people who manage fleets or drive long miles on a daily basis. Just be aware that you’ll probably want to complement it with some injector cleaner every so often.
The Lucas treatment is our favorite additive for people with a few different vehicles and motors to service, who want one treatment to work on absolutely everything.
It provides the same all-around benefits to diesel and gasoline engines, and is universally compatible. We also like it for its cost-effectiveness. It’s cheap, and usually pays for itself in fuel savings.
Stanadyne is one of the most comprehensive additives on the market.
It’s our top choice for people who want an all-around boost in large quantities. We like to think of it as a more industrial version of the Liqui Moly. It’s compatible with European injectors, provides detergents to keep your injectors clean, and boosts your fuel economy.
It also adds some cold weather benefits, which make it a good alternative to the Howe treatment for people in Northerly areas. We recommend it to people who want the benefits of Liqui Moly in a more convenient bottle for big tanks and heavy equipment.
Opti-Lube is the best option for people who need an all-around cleaner that really boosts lubricity.
It’s also our top choice for drivers who store lots of diesel, whether it’s in a fleet filling tank or barrels of biodiesel, since its stabilizers double the shelf life of diesels.
How to Choose the Best Diesel Fuel Treatment
Think about your budget:
You can get a rough comparison of costs by looking at the unit price (dollars per oz.), but it’s hard to get a firm number because additives vary so much in concentration and dosage size. In general, you’re looking at about 50 cents to 1 dollar/oz of additive. Various solutions cost more or less.
To figure out a good cost comparison for yourself, narrow down your list to the additives that suit your needs. Then, chart out the unit price, using the price per bottle divided by the number of ounces inside.
Next, make a note of how many ounces you’ll be using per gallon of fuel. Those two numbers will help you get a concrete sense of how much each additive will cost you to use.
While meeting your bottom line is always important, it’s our opinion that there are really too many cost factors to consider to use price as a deciding factor.
You’d have to figure out estimated fuel savings and money saved on maintenance/injector cleanings to start, and both those numbers would be estimates at best. You’re better off finding the additive that best suits your needs, and then finding a case rate or big bottle to get the unit price down as much as possible.
Consider your needs:
If you live in a colder area where temperatures stay below freezing for a good part of the year, gelling is a big concern. You want to find an additive that will prevent gelling in all your fuels, both when you’re pouring and when it’s sitting in your tank. Not all will do so, so be sure to check that the solution you buy is formulated for that purpose.
Cold weather can hamper startup, and cause serious clogs if you don’t use the right additives. Look for additives which lower the cold filter plugging point of your fuel. You can find a few different additives which also make diesel flowable below 0 degrees F. Cold weather features are a key aspect to look for, since not all performance additives have them integrated!
If you’re looking to improve fuel efficiency, you’ll want to look for an additive with plenty of detergents mixed in. Detergents serve a couple purposes which really boost economy. They keep injectors and combustion chambers clean of buildup from carbon and soot, which can really impede your car’s power, performance, and of course, efficiency.
Detergents also help break up any gunky bits or other imperfections in your fuel, which helps it burn smoother and more completely. In addition to the smoother engine sound and feel, you can see the difference in the exhaust. Fuels that are supplemented with detergents burn visibly cleaner. That’s because the imperfections have been burned cleanly, rather than belched out as dirty smog.
The specific type and grade of diesel you run will narrow down your options quite a bit. Additives list their compatible fuel grades on the bottle, so it should be easy to tell which additives are appropriate for your fuel.
If you buy a branded diesel, you should have a look at the company’s info listings to see which detergents or lubricants are already in the fuel. That’ll help you figure out where the weak points are, and how best to complement your fuel.
If you run low sulfur or ultra-low sulfur diesel in your vehicles, you almost certainly need an additive with lots of lubricity. For drivers who don’t have a consistent supply of fuel, we’d recommend an all-around booster to help compensate for the poorer tanks.
If you use biodiesels, you probably don’t need to add as much lubricity. However, you’ll probably want to up the detergent, to cull out any imperfections in the fuel. Biodiesel is a bit less refined by nature than the fill station varieties.
If your fuel comes from a personal tank, you probably want to add a stabilizer to extend the storage life of your diesel. Diesel is less stable than gasoline, so if you’re holding lots of fuel on your property or in a fleet tank, make sure you back it up with extra stabilizers.
The big thing to think about as far as motor is the age of your vehicle. Newer diesels have more finely tuned, technical injectors which aren’t compatible with all additives.
You’ll need to check for a solution which is formulated and tested to work well on these newer engines. Older motors will be fine with almost any additive, but you might want to choose a solution with lots of detergents to clean out built-up deposits.
You can use Amazon’s garage tool to check compatibility for any make and model on the market, and even plug the year in. If you’ve got a vehicle that’s been modified substantially, it might be a good idea to double check with your mechanic or dealer.
Most American diesels, especially the low and ultra-low sulfur kind, have lower lubricity than most injectors are designed to handle. In a recent study, 50% of sold diesel fuels were below manufacturer recommendations for lubricity ratings.
Since American diesel fuel doesn’t flow as easily, and can stick more easily to injectors, it tends to burn less efficiently. Lubricity is also important in diesels because, unlike gasoline engines, diesel engine components are mostly fuel-lubricated, and aren’t supplied by engine oil.
Low lubricity ratings cause faster wear on key components, and mean a much shorter life for your engine. That’s especially a problem on modern diesels and European makes.
Look for an additive that will substantially boost lubricity. It’s measured by cetane ratings, with the higher numbers being the most optimal. Don’t go for vague claims about lubricity, either. Any reputable manufacturer will list a specific rating, and some sort of test backing that rating up.
If you’re not sure if one of these additives is the best choice for you, check out the top selling options on Amazon! You can compare prices, and check compatibility with your specific vehicle. Don’t forget to visit https://fuelinjectorcleaner.xyz/ for more product reviews!