Winter is the time of year that really puts diesel trucks and tractors to the test. Sure, a boosted engine loves cold air, but you know what doesn’t? The fuel that makes these workhorses run. That’s why there are so many additives on the market meant to prevent diesel from gelling up, and companies make lots of other claims about their products, too. But how well do they actually work?
That’s what Todd from the Project Farm YouTube channel set out to determine. This guy is a ridiculously thorough tester, and for good reason—people who rely on their machinery need their rigs to run right, even in the coldest temperatures. That’s why he goes through the trouble of putting these additives through different trials relating to anti-gel capabilities, lubricity, oxidation prevention, and cetane properties.
Todd collected bottles of additives from the major players: Hot Shot’s Secret, Peak, Power Service Diesel, Amsoil, Archoil, STA-BIL, Optilube, Howes, Stanadyne, Ford, and Lucas. Every diesel truck owner has their preferred brand it seems. These experiments buck anecdotal evidence in favor of real results, and while some tests are a bit more subjective than others, I respect Todd’s methodology big time.
First up is the lubricity test. Here, Todd breaks out a stinkin’ energy use meter to determine how hard the test rig has to work to turn a wheel while immersed in the fuel. There’s also a pin mounted atop the test rig that the wheel makes contact with, so in addition to measuring the energy required to keep the wheel spinning, he also measures the wear on the pin with a micrometer. The Archoil product was the best performer in this test with a small 5.17-millimeter wear scar on the test pin, with Hot Shot’s Secret right behind it with a 5.2mm mark. And while the Lucas anti-gel (9.21mm) and Stanadyne (9.07mm) additives weren’t much better than untreated diesel (9.34mm), neither of them claimed to improve lubricity. Howes does, and it faired poorly with an 8.8mm mark.
Then it’s time to test these additives’ abilities to stave off gelling. Normal ultra-low sulfur diesel has a gel point of around 10 to 15 degrees Fahrenheit, and Todd really tests these products by adding the recommended amount to jars of diesel and placing them in a freezer set at -38 degrees Fahrenheit. It’s harder to measure the results of this trial quantitatively, but visual observations of fuel clouding and viscosity put the Peak and Hot Shot’s Secret additives at the top of the list. STA-BIL, AMSOIL, and Archoil were close behind, but the Lucas and Stanadyne additives couldn’t keep the diesel from freezing into a solid brick. This test isn’t going too well for them.
Todd then doubles the recommended dosage of each additive to see how well it performs in the same sub-zero conditions. Howes, Power Service Diesel, Peak, Ford, Amsoil, and Hot Shot’s all do a fair job, but each test jar is still pretty cloudy. The Stanadyne and Lucas jars are no longer frozen, though there’s still drastic gelling at the bottom of the container.
Next, Todd treats pieces of bare steel with each additive and sprays them with a mixture of hydrogen peroxide, vinegar, and salt. That’s his special concoction to form an “aggressive rusting agent,” and boy, does it work. Hot Shot’s Secret again comes out on top with a large section of the steel showing no signs of corrosion after 24 hours, but the Lucas-treated metal is covered in rusty spots that look more intense than the rest.
To test the products’ flammability, Todd pours a small amount on top of a metal cup and holds a lighter to observe how long it holds a flame. This is another subjective test, though still, I think you can see why it’s useful. Not every additive claims to boost cetane levels, and only Hot Shot’s, Power Service Diesel, Amsoil, Peak, and Opti-Lube seemed to make any difference in fuel burn.
Finally, and maybe most interestingly from a visual perspective, Todd brings out a new lineup of gelled diesel rescue products to test frozen and previously untreated fuel. None of the additives—which include Hot Shot’s, FPPF, Amsoil, CleanBoost, Howes, and Power Service Diesel—did much with the recommended dosage. That’s no surprise to anyone who’s tried following the directions on those products in a last-ditch effort. Todd then topped off each jar with the respective fuel rescue product and kept them at an ambient temp of 70 degrees Fahrenheit for an hour. Nearly every jar cleared up completely except for the Howes, which was pretty cloudy in comparison to the rest.
Altogether, I’m willing to bet this test is more thorough than anything you or I have done regarding diesel additives. And while I’ve done what I can to consolidate the results in this blog, you really ought to watch the Project Farm video to get the full picture. It’s 20 minutes long and amazingly, that’s somehow a perfectly enjoyable amount of time to watch someone talk about anti-gel products. That guy has charisma—it’s infectious.
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