I’m Kayla. I pull a small camper with my 2017 Ram 2500 Cummins. I also still baby my old 2005 Jetta TDI, and I run a small orange Kubota on weekends. I’m not fancy. I just hate rough starts, smoky tailpipes, and fuel that feels “meh.”
To keep an eye on the site when I’m out hiking, I rely on one of the cellular trail cameras that actually worked during my tests.
So, what’s the best diesel fuel additive? I thought one bottle would fix it all. It didn’t. Different jobs need different stuff. Let me explain.
I’ve detailed my personal pick for the best diesel fuel additive I’ve actually used if you want the full deep-dive.
If you’d like to compare how thousands of other drivers rank and review these same products, the quick-reference chart on 5StarShare lays it all out in one place.
My simple “best” checklist
- Starts easy in cold
- Less rattle and shake
- Fewer regens on the Ram
- A little bump in MPG (even 0.5 helps on long trips)
- Not crazy pricey and easy to find at truck stops
You know what? I also care about smell and mess. Some bottles leak. Some caps stick. Small things, but they add up.
If a pour gets sloppy, I just swing by the bucket and suds with the car wash soaps I actually use and trust so the diesel film doesn’t stick.
My go-to most days: Power Service Diesel Kleen (silver bottle)
Summer towing, this one just works. Last June, I pulled the camper from Colorado Springs to Moab with my Ram 2500. Three tanks with Diesel Kleen, dosed right at the pump. The truck felt calmer. Less injector tick. My Fuelly log showed a bump from 12.1 to 12.8 mpg over those tanks. Not huge, but real.
For even more perspective, an independent discussion on the effectiveness of Power Service Diesel Kleen gathers dozens of user experiences and performance notes that line up with what I’ve seen on the road.
On my Jetta TDI, I saw less haze on hard climbs and smoother idle. It also stretched out regens on the Ram a bit. I don’t have lab gear, but my trip notes went from “regen at 190-ish miles” to “around 220.” Could’ve been wind. Could’ve been the hills. But the seat-of-the-pants feel was better, and it stuck.
Pros:
- Easy to find at Walmart and truck stops
- Cetane bump you can feel
- Fair price per tank
Cons:
- The big jug can dribble if you rush the pour
- Doesn’t help with gelling (that’s a winter thing)
Winter hero: Power Service Diesel Fuel Supplement (white bottle) and Howes Diesel Treat
January, North Dakota, minus 10°F, truck sat all night. I treated the last fill with the white bottle, mixed per the cold chart, and parked nose to the wind. At 5 a.m., key on, it fired. A guy two spaces over gelled up and waited for a tow. I shared coffee. We both learned something.
While I’m waiting for the anti-gel to do its thing and the coffee to cool, I sometimes use Spdate—a quick, location-based dating site that helps travelers strike up conversations or meet locals, making those long, lonely stretches between fuel stops feel a little friendlier. Rolling through southwest Oklahoma on US-62, for example, I like to scan a regional bulletin for last-minute campsite leads or a local recommendation on the best brisket in town, and the classifieds on Backpage Lawton make that search painless by bundling all the community posts, personal ads, and gear swaps in one place.
Howes Diesel Treat has also saved my bacon. During the 2022 Ohio snap, the Kubota and the Jetta both stayed happy with Howes. It’s a bit thicker and smells less “chemical,” if that makes sense. My buddy who runs a small fleet swears by it for semis. I don’t argue. It works.
Pros (both):
- Real anti-gel help when the air bites
- Easy cold starts
- Good for peace of mind on road trips
Cons:
- You need to treat before the freeze hits
- Measure right; more isn’t better
Deep clean when things feel grubby: Hot Shot’s Secret Diesel Extreme
I use this as a reset once or twice a year. On my Jetta, I had a shaky idle and a puff of black on throttle. One bottle in a half tank, drove it hard on a warm day, and by day two the idle felt steady. The smoke faded. I even saw a small bump from 43 to 44.5 mpg on a longer run. It didn’t fix worn parts, of course. But it cleaned things well enough that I noticed.
A comprehensive third-party review of Hot Shot’s Secret Diesel Extreme dives deeper into how its injector cleaner ups power and mileage—pretty much mirroring my own results.
Pros:
- Strong one-and-done clean
- Helps with rough idle and soot
Cons:
- Costs more per treat
- The bottle smell sticks to your hands (gloves help)
For newer, picky systems: Stanadyne Performance Formula
When I had my 2011 Duramax, this was my “treat it nice” bottle. GM folks like it, and I get why. It quieted clatter and kept regens spaced out on long hauls to Kansas City. The truck felt crisp. The dosing neck is decent too.
Pros:
- Great lubricity for high-pressure systems
- Solid cetane boost
- Good for long-term care
Cons:
- Pricey
- Not in every small-town store
For Euro diesels and Sprinter vans: Liqui Moly Super Diesel Additive
My Jetta TDI loves this stuff. It smooths light throttle and trims the faint “tick” I hear with cheap fuel. I also used it on a friend’s Sprinter van after a lot of short city trips. Less smoke on pull-out and smoother shifts (well, the shifts weren’t smoother; the engine just wasn’t surging as much, which made the van feel calmer).
Pros:
- Clean idle and gentle manners
- Nice narrow spout for clean pours
Cons:
- Smaller bottles add up in cost
- Harder to find at gas stations
Quick picks by use case
- Best all-around (warm months): Power Service Diesel Kleen (silver)
- Best cold weather: Power Service White Bottle or Howes Diesel Treat
- Best one-shot clean: Hot Shot’s Secret Diesel Extreme
- Best for modern common-rail care: Stanadyne Performance Formula
- Best for TDIs/Sprinters: Liqui Moly Super Diesel Additive
How I test stuff (not fancy)
- I log fill-ups in Fuelly. I also note wind, load, and hills.
- I add at the pump, so the swirl mixes it.
- I start clean: new fuel filter and water drained.
- I stick to the dose. Over-treating never helped me.
- In real cold, I treat before the freeze and keep the tank closer to full.
Small tip: store the bottle in a zip bag in the side bin. If it drips, you won’t smell it all week.
Things I didn’t love
- Lucas Upper Cylinder Lubricant for diesel: In my Jetta, it made the exhaust smell heavy and didn’t move mpg at all. The Ram didn’t care for it either—noisy starts stayed noisy.
- Archoil AR6200: It worked fine, but it’s pricey and I had to mail-order it. Great tiny bottle, though. Just not my daily pick.
So, what’s “best”?
For me, it’s a two-bottle life:
- Power Service Diesel Kleen in warm months for smooth power and a small mpg bump.
- Power Service White or Howes in winter, because starting beats towing.
When things feel dirty, I run Hot Shot’s Secret Diesel Extreme for a fresh start. If I’m babying a modern, high-dollar system, I grab Stanadyne. Simple, steady, done.
One last thing—fuel quality swings a lot by station and season. An additive won’t fix a bad injector or a clogged filter. But used right, it can take a good tank and make it feel just a bit better. And on a long road, that little bit feels big.