2026 test5 productsEngine Oil & Fluids
Which Motor Oil Additives Brand Wins?
We compared 5 motor oil additives options head to head. Liqui Moly MOS2 came out on top. See the measured results, the runner-up, the budget pick, and a link to the full test video.
Winner
Liqui Moly MOS2
Price shown in test: $11
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Runner-up
Bestline (won the realistic blended wear scar test, but had the worst evaporative loss of the group)
Price shown in test: $25
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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 | Real World Vehicle Test | Evaporative Loss Heat Test | New Oil Flow Speed | Cold Oil Flow Test | Wear Scar Lubricity Test | Oil Lab Analysis |
|---|---|---|---|---|---|---|
| 1Liqui Moly MOS2 Anti-Friction Engine Treatment$11 | tested in a 2003 Chevrolet Suburban with over 320,000 miles; fuel economy dropped slightly from 17.36 to 16.86 mpg though some rain occurred during the with-additive run; 0 to 60 time was 8.66 seconds versus an 8.64 second baseline, essentially no detectable difference in power; cranking wattage to start the cold engine dropped from 1,516 W to 1,392 W, about 124 W less, suggesting easier cranking | lost only 2.83 g over 2 hours at high heat, less evaporative loss than pure Pennzoil Ultra Platinum motor oil's 3.13 g, one of only two additives (with Prolube) that outperformed plain motor oil on this test | 1.32 seconds, slightly slower than pure motor oil's 1.3 seconds; added some viscosity to the oil | trailed pure motor oil both before and after heat exposure; finished in 1 minute 11 seconds new, 1 minute 11.83 seconds after heat exposure, versus about 1 minute 2 seconds and 59 seconds for motor oil | 100 percent concentration wear scar was 5.88 mm versus 5.37 mm for pure motor oil; blended with motor oil at the proper ratio and exposed to heat, the wear scar was 5.44 mm, still larger than the 5.37 mm of pure motor oil but close | increased the oil's MOS2 content over pure motor oil; like most additives tested, reduced overall detergent/dispersant, zinc content, and total base number slightly compared to pure Pennzoil |
| 2Lucas Heavy Duty Oil Stabilizer$12 | no dedicated real world vehicle mpg or 0 to 60 test described in the transcript, unlike the other four additives | lost 3.15 g, almost identical to pure motor oil's 3.13 g loss | 2 seconds, by far the slowest of the group tested alongside it (motor oil, Liqui Moly, Bestline), added quite a bit of viscosity to the oil | by far the slowest at both stages, just under 1 minute 54 seconds new and just over 1 minute 44 seconds after heat exposure | 100 percent concentration wear scar was 5.45 mm, not quite as good as pure motor oil; blended with motor oil at the proper ratio and exposed to heat, the wear scar tied pure motor oil exactly at 5.37 mm | presenter notes it does not have much anti wear additive and is mostly a viscosity enhancer; like most additives tested, reduced overall detergent/dispersant, zinc content, and total base number slightly compared to pure Pennzoil |
| 3Bestline Engine Treatment with nano diamond technology$25 | tested in a Toyota 4Runner; fuel economy dropped from 23.42 to 21.21 mpg, a loss of 2.2 mpg; 0 to 60 time improved slightly from 8.24 to 8.19 seconds (0.05 seconds faster); cranking wattage to start the cold engine increased from about 2,020 W to 2,105 W, about 85 W more than with just motor oil | lost 4.77 g, about 41 percent more evaporation than pure motor oil, the worst performer on this test | 1.27 seconds, faster than pure motor oil's 1.3 seconds; thinned the oil out slightly | the fastest flowing oil at both stages, 55.5 seconds new and 51.1 seconds after heat exposure, both faster than pure motor oil | 100 percent concentration wear scar was only 1.62 mm, very small; blended with motor oil at the proper ratio and exposed to heat, the wear scar was 4.70 mm, the only additive in this test that outperformed pure motor oil's 5.37 mm in the realistic blended and heated test | increased the oil's MOS2 content over pure motor oil; viscosity at 210 F was in the lower range of normal; like most additives tested, reduced overall detergent/dispersant, zinc content, and total base number slightly compared to pure Pennzoil |
| 4Prolube$39 per quart container | tested in a 2020 Chevrolet Silverado with a 5.3L V8; fuel economy improved from 21.92 to 23.4 mpg, about 1.5 mpg better; 0 to 60 time improved from 7.7 to 7.55 seconds; presenter notes he is not convinced the fuel efficiency and power gains will last more than a few hundred miles since the additive is new to that engine | lost 3.06 g, slightly less than pure motor oil's 3.13 g, one of only two additives (with Liqui Moly) that outperformed plain motor oil on this test | not tested | struggled badly with cold temperature after heat exposure, by far the slowest at just over 2 minutes 8 seconds; new oil flow speed relative to the other group (Arch Oil comparison) was not too far behind motor oil | 100 percent concentration wear scar was only 2.08 mm, very small; blended with motor oil at the proper ratio and exposed to heat, the wear scar was 5.84 mm, larger than pure motor oil's 5.37 mm and the worst result of any product in the realistic blended and heated test, described as heat really damaging the product | the only product that boosted phosphorus content over stock motor oil; lowered the pure Pennzoil's total base number the most of any additive tested, by 5.8 points, suggesting it contains an acid that consumed the oil's reserve alkalinity |
| 5Archoil AR9100 nanoborate lubrication technology$40 for a 16 oz bottle, treats just over 13 quarts of oil | not tested in a vehicle; instead tested in a fuel injected generator that ran 22 minutes 48 seconds on a full tank of pure fuel, versus 22 minutes 33 seconds with Arch Oil added, coming up 15 seconds short of the regular fuel baseline | lost 3.42 g, more evaporative loss than pure motor oil, finishing fifth of the six samples on this test | 1.28 seconds, the fastest of its comparison group (versus motor oil and Prolube); thinned the oil out slightly | flowed quickly both new and after heat exposure, finishing at just over 55 seconds new and 57.5 seconds after heat exposure, close to or slightly better than pure motor oil | 100 percent concentration wear scar was only 1.08 mm, the smallest of any product tested; blended with motor oil at the proper ratio and exposed to heat, the wear scar was 5.54 mm, larger than pure motor oil's 5.37 mm | the only additive that increased detergent/dispersant content over pure Pennzoil, had a very high dosage of potassium and boron (likely from the potassium borate friction reducing ingredient) and sodium, and had by far the highest total base number of any sample tested at 12.2 |
How it was tested
- new oil flow speed at ambient temperature
- cold oil flow speed at minus 40 degrees Fahrenheit, new and after heat exposure
- real world in-vehicle fuel economy and 0 to 60 mph acceleration test (different vehicle used per additive)
- cold engine cranking amps and wattage test
- Noack-style evaporative loss (heat exposure) test at high temperature for 2 hours
- lubricity wear scar test at 100 percent concentration and blended with motor oil after heat exposure
- independent oil lab analysis of wear metals, detergent/dispersant content, anti wear additives, viscosity, and total base number
“after all the testing, only Liquid Molly tied the motor oil. Unfortunately, none of the other products boosted with additives performed as well.”