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Even tried-and-true diesel motors need proper care and feeding to keep clattering along, and proper diesel fuel additives will help with just that. If you want your Volkswagen TDI or Duramax to ferry you into the heat death of the universe, then detergents, lubricants, and stabilizers will keep your fuel system in check for long life. Diesel additives will also improve fuel economy and restore lost performance from expelling all that nasty crud. However, it is a confusing, heavily saturated market, so allow me to lend a hand.
Enter The Drive’s buyers guide to the best diesel fuel additives on sale. From basic cleansers to comprehensive all-in-one treatments, every now and then or with every fill-up, there’s a product on this list for you. So scroll through, pop that fuel cap, and give your oil burner the nutrients it needs to keep its lifeblood flowing smoothly with these diesel additives.
Summary List
Best Overall: Hot Shot’s Secret Diesel Extreme
Best Value: Howes Diesel Treat Conditioner and Anti-Gel
Honorable Mention: Lucas Oil Diesel Deep Clean
Editor’s Personal Favorite: Sea Foam Motor Treatment
Best Diesel Additive For High Performance: Amsoil Diesel All-In-One
Best Diesel Additive For Winter: Hot Shot’s Secret Diesel Winter Anti-Gel
Best Diesel Additive For Classics: REV X Distance+ Gold Diesel Treatment
Our Methodology
Our additive guide was primarily conjured through extensive research, diving deep into manufacturer specs and real-world consumer feedback. Amazon and AutoZone were highly resourceful, providing a thorough insight into objective data and buyer input. Manufacturer sites such as Howes, REV X, and Amsoil, as well as numerous online forums, bolstered our data and enhanced our understanding of general fuel additive characteristics.
The all-star diesel additives were typically the most well-received in their respective fields, with proven cleaning capabilities, performance benefits, and efficiency improvements. We ignored additives with little-to-no data or consumer input in favor of products with trusted real-world backing.
As always, readers are welcome to learn more about how The Drive generally curates its buyer’s guides and product reviews.
Best Diesel Fuel Additives Reviews & Recommendations
Best Overall: Hot Shot’s Secret Diesel Extreme
Pros
- Highly potent formula for semiannual deep cleaning
- Well-rounded formula for cleaning, fuel storage, and cetane boosting
- Suitable for a wide variety of diesel engines
- Noticeable improvements in smoothness and economy
Cons
- Not particularly safe for everyday use
- Missing anti-gels for true all-in-one use
Hot Shot’s Secret Diesel Extreme is a returning winner from a previous iteration of this guide, lauded for its strength and effectiveness. As an occasional deep-cleaning treatment, this small bottle does wonders in expelling all that funky stuff that could clog fuel lines and injectors in diesel motors. The additive is touted as an all-in-one, including lubricants, stabilizers, and moisture dispersants for prolonged service life, regardless if your vehicle is a garage queen or a daily driver. Cetane boosters help engines achieve a complete burn for improved performance, making it a viable choice for many machines, from agricultural and industrial machines to racing vehicles and commuters.
One consumer recounts using Diesel Extreme to flush buildup in their Volkswagen TDI while improving fuel efficiency in their daily use trucks — up to three miles per gallon.
Caveats are few and far between, but they’re standout. Hot Shot’s Secret does not regard the strength of this formula to be particularly safe for frequent, everyday use. This additive is recommended as a semiannual treatment and also sells. Additionally, there are no anti-gels.
Best Value: Howes Diesel Treat Conditioner and Anti-Gel
Pros
- Dirt-cheap bottles
- Highly potent
- Winter-capable anti-gel properties
- Potentially classic car-friendly
Cons
- No disclosed cetane booster
- No defined use interval
Frugal-minded diesel fanatics should take great interest in Howes Diesel Treat Conditioner and Anti-Gel, which aims to rival its peers for one hell of a bargain. Diesel Treat delivers cleaning, lubrication, and winter-friendly anti-gel properties in a 32-ounce bottle for a mere $10. Two whole Abraham Lincolns! For reference, rivals charge at least a few dollars more for half the fluid ounces.
While capable as an all-in-one product, Diesel Treat has garnered a loyal customer base as a cost-effective winter additive. Its anti-gel properties have found use in everything from tractors to diesel econoboxes and even motorhomes. Its lubricants have also been utilized in older diesel vehicles to supplement the relative lack of lubricants in modern diesel formulas.
It’s difficult to fault such a well-received bargain deal, but there are some stipulations when pursuing cost-effectiveness. It’s widely assumed that this product is suitable for everyday use, but no specifically disclosed use interval exists. Those looking for a more complete performance enhancer will also be disappointed in the lack of cetane boosters.
Honorable Mention: Lucas Oil Diesel Deep Clean
Pros
- Targets gunk and dirty particulate filters
- Perfect for simply wanting to boost power and economy
- Safe for everyday use
Cons
- Limited uses
Buyers looking for a quick and easy cleaning solution for their oil-burners should give Lucas Oil Diesel Deep Clean a shot. This additive emphasizes cleaning lines and particulate filters for restoring dulled performance and fuel economy. It may sound narrow-focused in its approach, but that results in doing its intended task remarkably well, having found a customer base among newer diesel owners looking to upkeep their fancy new metal. Diesel Deep Clean is widely used as a simple preventative maintenance solution, delivering perceptible improvements in throttle response and efficiency as a result of clearing carbon buildup.
Prospective buyers interested in proper care and feeding for aging diesels may be left disappointed. As a highly-focused fuel cleaner, there aren’t many other talents up the Diesel Deep Clean’s sleeve. There are no anti-gels for winter, nor are there stabilizers for storage or cetane boosters for a clean burn. Buyers recommend pretreating with true all-in-one deep treatments before hopping over to such a simple additive.
Editor’s Personal Favorite: Sea Foam Motor Treatment
Pros
- Versatile formula for anything and everything under the sun
- Proven fuel system cleanser and stabilizer
- Winter-capable anti-gel properties
- Safe for everyday use
Cons
- Not the most potent formula
- Not a savior for all classics and could pose risks
Internet chatter places Sea Foam Motor Treatment on a pedestal as some sacred magic-in-a-can that sounds too good to be true, but I can attest to its spread of talents. Sea Foam Motor Treatment is a hallowed additive for a reason.
This additive is one of the most well-rounded additives on sale. Sea Foam is both a fuel and an oil additive for diesel and gasoline vehicles. It’s suited to heavy machinery, passenger cars, recreational toys, and marine engines. If it’s motivated by internal combustion, Sea Foam can bless it. The simple yet effective suite of ingredients works together to clean, disperse water, lubricate, and stabilize fuel, enabling this product to function as a viable all-in-one that’s safe for everyday use. It’s done wonders for numerous enthusiasts, including myself and my 1987 Nissan Be-1, which the additive helped in starting and idling while wiping out its bad habit of vapor locking.
Unfortunately, its mild dosage equates to having to use a fair amount if you’re looking to flush out a nasty fuel system. While it is a safe product, you may find yourself using quite a lot of it. Thankfully, it’s almost as affordable as Howes yet far more plentiful.
Best Diesel Additive For High Performance: Amsoil Diesel All-In-One
Pros
- Another multi-talented fan favorite
- Winter-capable anti-gel properties; vastly improved cold flow
- Combo formula of Amsoil’s injector cleaner, cetane boost, and anti-gel
- Proven performance and economy gains
Cons
- A little pricier than its peers
Amsoil Diesel All-In-One is a fierce competitor in this field and one of the most acclaimed diesel additives on sale, almost unseating the Diesel Extreme as our Best Overall. This product puts up a hell of an argument for buyers looking for maximum cleaning with every fill-up. Lubrication, stabilization, and cetane boosting fall under its belt, making it appealing to owners of older diesels or vehicles that simply live in storage. Unlike many of its peers, Amsoil separates itself by also including anti-gelling properties, enabling winter use and completing this product as a true all-in-one additive.
The performance of this additive is almost infallible aside from its slightly steeper price tag. At $14 for a 16-ounce bottle, it undercuts its closest rival, Hot Shot’s Secret Everyday. but is more expensive than Howes Diesel Treat and Sea Foam Motor Treatment. However, it’s safe to say that buyers looking for the complete package won’t mind spending a few more dollars, especially given its winter capabilities, which greatly outclasses Howes.
Best Diesel Additive For Winter: Hot Shot’s Secret Diesel Winter Anti-Gel
Pros
- Specially formulated just for winter use
- Awesome squeeze bottle with measurement nozzle
- Potent cetane booster for maintaining performance and improving cold starts
Cons
- Requires proper storage for maximum effectiveness and longevity
Hot Shot’s Secret won’t put anti-gel in their Extreme or Everyday formulas, but they will gladly sell you their Diesel Winter Anti-Gel formula. This diesel additive doesn’t skimp out to be a one-trick pony but rather creates a kind of all-in-one product with a significantly heightened emphasis on winter drivability. It reduces the pour point—the temperature where fluid loses its flow characteristics–to negative 65 degrees Fahrenheit, perfect for escapades in an Artic Truck. Similar to its stablemates, this additive retains its ability to clean fuel, lubricate parts, help with cold starts, disperse moisture, and boost cetane by as high as seven points. As a cherry on top, the additive is packaged in a unique squeeze bottle with a measuring nozzle that can store roughly one ounce before pouring.
Diesel Winter Anti-Gel’s spread of talents makes it a lovable winter companion, but it does raise an eyebrow as to how it’s not a part of Hot Shot’s Secret’s Everyday or Extreme additives. Separate winter formulas are not uncommon in this field, but having to hunt for one come winter seems like an unnecessary step when Amsoil and Howes include anti-gels as part of the typical all-in-one package.
Best Diesel Additive For Classics: REV X Distance+ Gold Diesel Treatment
Pros
- Stout 12-point cetane boost
- Heightened emphasis on lubrication, stabilization, and anti-corrosion
- Available in ingenious squeeze bottle with measurement nozzle
- Incredibly strong dosage
Cons
- Steep price for a 16-ounce bottle
- No anti-gel for cold weather use
A nifty treat for diesels that have seen a lifetime of miles, REV X’s Distance+ Gold additive will be that special sauce to keep them clattering. As an all-in-one for nearly any diesel engine on the road, old or new, this product touts a greater emphasis on lubrication and fuel stabilization. The product claims to deliver as high as four times the lubrication of rival diesel additives, including REV X’s own standard additive formulas, to supplement the loss of sulfur in modern diesel fuels – sulfur was a handy lubricant but also corrosive and toxic.
An added focus on stabilization will prove much appreciated by gearheads whose collector machines live from car show to car show. REV X insists that its additive will keep fuel usable in storage for up to 12 months. And a cetane boost as high as 12 points will help these diesels achieve the best possible burn no matter what model year.
This additive puts up bold claims, which are thankfully supported by customer acclaim and commendable performance, comparable to Hot Shot’s Secret. But such performance will cost a pretty penny, or figure 3,500 of them for 16 ounces.
Our Verdict
Hot Shot’s Secret Diesel Extreme is christened our Best Overall yet again for its strength, effectiveness, and resounding acclaim across a variety of owners. Lucas Oil’s Diesel Deep Clean additive is a worthwhile, quality product for those looking for a more usable cleanse to keep their diesels running fresh every day. And if those are a little steep on the price, allow me to recommend Howes Diesel Treat as our Best Value winner, as it delivers excellent cleaning and anti-gel capabilities for one heck of a steal.
Things to Consider Before Buying Diesel Fuel Additives
Cleaners/Detergents
These are the primary selling points behind every additive, including the cheaper ones. Detergents are the base oils and hydrocarbons designed to clean out sludge, unclog injectors and filters, and liquefy dunk to be flushed out and are common ingredients in nearly all diesel additives. In addition to freeing up the fuel system, using detergents can prevent the corrosion harmful deposits cause.
Exercise caution with additives using certain alcohols as a detergent; they can degrade plastics, rubbers, and metals while reducing the fuel’s flashpoint. Sea Foam cleverly uses oil-derived isopropanol — isopropyl alcohol — as it acts as a residue remover without corroding or drawing moisture as other alcohols would.
Stabilizers
These ingredients ensure your diesel remains a potent, usable fuel, even after spending much time in storage. Additives with stabilizers are sought after by classic car enthusiasts, marine vehicle owners, and other demographics whose machines don’t always see the light of every passing day. Stabilizers prevent fuel from breaking down and drawing moisture, enabling it to still be usable for the long haul. Many diesel additives with stabilizers are rated to keep fuel fresh for anywhere between 12 to 24 months in storage.
Anti-Gel
Anti-gels are crucial ingredients in many all-purpose additives and every winter additive. As the name suggests, they keep the paraffin wax, a lubricator in diesel, from solidifying in extreme cold. Paraffin wax that solidifies can settle in your tank and block fuel filters. Anti-gels work to lower the freezing point of diesel and its cold filter plug point, or CFPP, the point at which diesel can no longer flow through a certain filter.
Cetane Booster
Cetane is kinda-sorta akin to octane for gasoline. A cetane rating indicates how well diesel fuels burn in an engine. The higher the rating, the better, the more complete a burn. Cetane boosters work similarly to octane boosters to help diesels, especially high-performing modern diesels, extract the most performance and economy by upping the cetane number by a few points to achieve a more complete burn. It’s a commonplace ingredient in most premium brands, such as Amsoil and Hot Shot’s Secret, with nearly all formulas containing some level of cetane booster.
Diesel Fuel Additive Pricing
For the most part, even the pricier diesel additives are cost-effective solutions to prolonged engine life and performance. Expect nearly all 16-ounce bottles of additives to retail between $10 and $20, with the median hovering slap bang in the middle. Prices increase with quantity, but the overall value increases as you start to buy in bulk.
FAQs
You’ve got questions. The Drive has answers.
Q: What are the benefits of diesel additives?
A: Diesel fuel additives, at their core, are designed to clean out the gunk clogging injectors and filters in fuel systems. In turn, this improves fuel economy, performance, and engine longevity. Beyond that, many formulas improve lubrication, stabilize fuel for long-term storage or winter driving, or boost cetane.
Q: How often should I use diesel additives?
A: Most diesel additives are intended for daily use with every fill-up unless stated otherwise. Some especially-potent formulas are for deep cleans and should be used once or twice a year. Overusing high-strength deep treatments could harm and eat away at fuel system materials.
Q: Are there risks to diesel fuel additives?
A: There are risks to using lesser quality additives or overusing high-strength treatments. Undesirable alcohols or excessive use of deep treatments could degrade plastics, rubbers, and metals in fuel systems, an especially daunting risk in aging engines. Ensure your chosen product is of quality and safe for everyday use.
