2025 test15 productsFuel & Additives
Which Fuel Stabilizer (plus A Separate 1-year Headlight Restoration Kit Durability Check-in) Brand Wins?
We compared 15 fuel stabilizer (plus a separate 1-year headlight restoration kit durability check-in) options head to head. Sta-Bil came out on top. See the measured results, the runner-up, the budget pick, and a link to the full test video.
Winner
Sta-Bil
Price shown in test: $6 for 8 oz
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Budget pick
Sta-Bil
Price shown in test: $6 for 8 oz
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The measured results
Every number below is read straight from the test. Scroll sideways to see all measurements. Products are listed in the order they finished.
| Product | Claims | Flammability (low alcohol content) | 3-year corrosion test | Rubber hose hardness (durometer, vs 52.5 baseline) | 20-month staleness/flammability test | Generator run test (20-month-old fuel) | Flammability | 3-year corrosion test (control) | Rubber hose hardness (durometer, control baseline) | 20-month staleness test (control) | Generator run test (20-month-old fuel, control) | Kit contents | Original process (from the prior review) | Original placement (review from about a year before this video) | 1-year UV exposure re-check (this video's actual new test) | Original process | Original placement | 1-year UV exposure re-check |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1Sta-Bil$6 for 8 oz | claims effective for all ethanol blended fuels; made in USA; safety data sheet lists 95% hydrotreated light petroleum distillates and 5% isopropylated phenol | not very flammable on its own | the pot metal showed no corrosion at all, not even a trace; the treated fuel had not fully evaporated (Sta-Bil helped prevent evaporation), though the leftover fuel itself was not flammable; received the best possible corrosion rating of 1 | 48.5, the lowest (softest) of all products tested, taking the lead for least rubber hardening | stale but beginning to ignite, performing the best of the group at that point; received a rating of 4.5 on the 1-5 flammability scale (1=excellent), just a little better than every other product, which all received a 5 | fired up in about 2.5 seconds with no starting fluid needed, about the same as Star Tron; ran pretty smooth; spark plug afterward looked almost as good as new; tied Star Tron for the best generator-test rating of 3 on the subjective performance scale (K100 was third at 3.5) | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested |
| 2Star Tron$7 for 8 oz | treats up to 48 gallons of gasoline, under 10 cents per gallon; claims to stabilize fuel, improve performance, and clean the fuel system; made in USA; contains pretty much 100% hydrotreated light petroleum distillates | not tested | did not stop the corrosion; some pitting and pretty bad damage to the metal; narrator says it's hard to believe how big the difference is compared to Sta-Bil | 55.5, slightly harder than the untreated baseline | was not able to keep the fuel fresh, and it would not light; part of the group of products rated 5 (worst) on the flammability scale | fired right up in about 2.5 seconds with no starting fluid needed, ran the smoothest yet at that point, spark plug looked pretty clean afterward, described as 'definitely the best yet' in this specific test; tied Sta-Bil for the best generator-test rating of 3 | not flammable on its own | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested |
| 3K100$12 for 8 oz | claims to treat up to 16 gallons, about 75 cents per gallon; claims to stabilize fuel for up to 2 years; made in USA; contains ethylene glycol plus alcohol-based ingredients | not tested | looked a lot better than Star Tron, with a small amount of corrosion/sludge; performed a lot better than Star Tron and definitely better than untreated fuel; received a corrosion rating of 2, second best behind Sta-Bil's rating of 1 | 51, a very small amount softer than baseline, briefly the best result before Sta-Bil was tested at 48.5 | did not look too bad but was pretty stale; part of the group of products rated 5 (worst) on the flammability scale | needed a little help from ether to start; engine sounded a little rough but did not need starting fluid; spark plug looked really good, about as clean as Star Tron's; finished third on the generator-test rating at 3.5 | definitely more flammable than Sta-Bil and Star Tron, as expected from an alcohol-based product | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested |
| 4SeaFoam$10 for 16 oz | made in USA; contains petroleum distillates, a hydrocarbon-based solvent, and alcohol | not tested | did not stop the water-contaminated E10 fuel from causing a tremendous amount of corrosion to the pot metal; quite a bit of corrosion, described as nasty-looking | 52.5, identical to the untreated baseline, no protective effect | was not going to light at all; part of the group of products rated 5 (worst) on the flammability scale | needed 21 shots of starting fluid to finally get hot enough to burn, versus only 2 shots for untreated gasoline; ran with a lot more smoke than untreated gas and only powered the halogen lights for a few seconds; spark plug picked up a lot of carbon, though narrator notes uncertainty whether that was combustion residue or SeaFoam's known cleaning action | seemed just as flammable as K100 | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested |
| 5Marvel Mystery Oil$14 for 32 oz | does not claim to be a fuel stabilizer, tested anyway; claims to improve compression, power, and MPG; made in USA; contains hydrotreated light petroleum distillates, phosphoric acid, and a couple of dichlorobenzenes | not tested | plenty of corrosion on the metal, though it looked better than the metal in the SeaFoam container | 52.5, identical to the untreated baseline | in pretty bad shape; part of the group of products rated 5 (worst) on the flammability scale | needed a shot of ether to start, producing a big puff of smoke, but did not need a follow-up shot of starting fluid; spark plug had quite a bit of carbon on it for such a short engine run | not very flammable compared to K100 and SeaFoam | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested |
| 6Yamalube fuel stabilizer and conditioner plus$20 for 32 oz | about 99.9% petroleum distillates | not tested | did experience some corrosion but not as much as untreated fuel; the treated fuel itself turned very dark, almost as dark as used motor oil | 52, just a little softer than average, a minor effect | too stale to run; wasn't any more successful than SeaFoam; part of the group of products rated 5 (worst) on the flammability scale | needed a little help from starting fluid to get going, then didn't need more; spark plug wasn't too bad but not quite as clean as Sta-Bil's | not very flammable, similar to Sta-Bil and Star Tron | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested |
| 7Untreated E10 gasoline | not tested | not tested | not tested | not tested | not tested | not tested | not tested | the water-contaminated, untreated E10 fuel caused a tremendous amount of corrosion to the pot metal, used as the baseline for comparison; fresh (non-aged) E10 fuel was noted separately as very flammable and lit very quickly, while the 3-year-old untreated sample would not run an engine at all | 52.5, used as the baseline against which all treated samples were compared | very stale | tested first; needed about 19 seconds of cranking, an air filter removal, and 2 shots of starting fluid to get running; ran roughly enough to power four halogen lights briefly; spark plug afterward showed quite a bit of carbon build-up for such a short engine run | not tested | not tested | not tested | not tested | not tested | not tested | not tested |
| 840:1 gas and 2-stroke oil premix | not tested | not tested | the two-stroke oil did not prevent corrosion; quite a bit of damage to the metal | 52.5, the same as the untreated baseline | did not hit hard at all and would not ignite without a lot more added heat; part of the group of products rated 5 (worst) on the flammability scale | tested last, deliberately, since it was expected to create the most carbon; needed a shot of starting fluid to start, produced a large puff of two-stroke smoke, ran rough and nearly stalled but recovered, held up under the halogen light load though sounding poor; ended with more spark plug carbon build-up than most of the other products | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested |
| 9Sylvania headlight restoration kit | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | drying towels, purifying compound, surface activator, UV block clear coat, and sandpaper | used the surface activator, sanded with water until white and hazy, applied clarifying compound, reapplied surface activator, rinsed, then applied the UV blocking clear coat; took about 21 minutes total, longer than most other kits | came out on top, first place | still looks good compared to the unrestored side; narrator says it held up the best due to its protective coating; finishes first place again in the durability re-check | not tested | not tested | not tested |
| 10Cerakote headlight restoration kit | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | 8 oxidation remover wipes, 1 surface prep pad, several grits of sandpaper, 2 ceramic clear coat wipes, and 4 application gloves | not tested | not tested | not tested | washed the headlight, used the oxidation remover wipes, scrubbed with a surface prep pad and water for 3 minutes, additional sanding, dried, then sealed with the ceramic clear coat wipes; took about 15 minutes total | second place; did a much better job than most other brands at providing a clear headlight finish | still looking pretty good compared to the competition; could benefit from another restoration but it would be easier this time; finishes second place again in the durability re-check |
| 113M headlight restoration kit | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | an assortment of sandpaper, a disc pad holder, and rubbing compound; requires a drill to use | not tested | not tested | not tested | cleaned with soap and water, sanded away the oxidation using several grits, then applied rubbing compound for a smooth finish; took about 10 minutes total; did not include a protective coating | tied for third place with Rain-X, described as too close to call | moved up to third place outright; headlight is now in pretty bad shape and needs restoring again, since the kit did not include a protective coating |
| 12Armor All headlight restoration kit | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | 4 patches for step one and 2 patches for step two, plus a UV sealant protection pouch | not tested | not tested | not tested | cleaned and dried the headlight, used two oxidation removal wipes for close to 5 minutes, then applied the protective coating top to bottom and cured it for 24 hours | sixth place; the restoration wipes could not remove all the oxidized material, though the top coat did reduce its appearance | moved up to fourth place; the restored side looks better than the unrestored side but still needs another restoration; the top coat appears worn away and the headlight is again in very bad condition |
| 13Rust-Oleum headlight restoration kit | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | a precision wipe-it, professional lens polishing pads, nitrile gloves, and one microfiber towel; was the least expensive kit in the original lineup | not tested | not tested | not tested | wetted the lens with water and used a green polishing pad to remove oxidation, but made little progress before the pad was used up; applied a protective coating afterward; took about 11 minutes total | fifth place; did a decent job removing oxidation, but the protective coating was not as smooth or transparent as some other brands | looks like it's ready to be restored again, the lens has oxidized quite a bit; stays in fifth place, marginally better than Rain-X |
| 14Rain-X headlight restoration kit | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | a drill attachment, sanding disc, premium polishing pad, and several other items | not tested | not tested | not tested | cleaned and dried the lens, sanded with the drill attachment until the yellow coating was removed, polished with the premium buffing polish, then sealed with premium wipes; took about 9 minutes total | tied for third place with 3M | dropped to sixth place; the protective coating did not last, and it is now hard to tell which side was actually restored |
| 15Meguiar's headlight restoration kit | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | not tested | cleaning pads, a cleaning solution, and headlight coating | not tested | not tested | not tested | cleaned with the pads and solution until achieving a uniform frosted appearance, then applied two coats of the headlight coating | seventh (last) place; did not include an abrasive or cleaning solution strong enough to remove all the previous oxidation | stays in seventh (last) place; both sides of the headlight look pretty bad, hard to tell which side was restored |
How it was tested
- 3-year corrosion resistance test on ethanol E10 gasoline contaminated with water, containing pot metal (carburetor alloy) and rubber fuel hose samples
- flammability comparison of the fuel/stabilizer mixtures after 3 years of storage
- rubber fuel hose hardness (durometer) after 3 years of ethanol/stabilizer exposure, versus an untreated baseline
- a second, independent 20-month fuel storage test in a climate-controlled environment, rating flammability/staleness on a 1-5 scale
- running a fuel-injected generator on the 20-month-old stabilized fuel samples, measuring starting difficulty, starting fluid needed, smoke, and spark plug carbon buildup
- separate segment: a 1-year later durability re-check of seven headlight restoration kits from a prior review, assessed after a full year of UV and weather exposure
“In my opinion, none of the fuel stabilizers really performed all that well. However, if I had to choose just one product, I would definitely choose the Sta-Bil. IT'S THE MOST AFFORDABLE PRODUCT and it actually delivered some good. However, for preventing corrosion, Sta-Bil did by far the best job.”