Which Penetrating Oil Brand Wins?
We compared 6 penetrating oil options head to head. Liquid Wrench came out on top. See the measured results, the runner-up, the budget pick, and a link to the full test video.
Liquid Wrench
Price shown in test: $4 a can, least expensive product tested
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ATF/Acetone
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Liquid Wrench
Price shown in test: $4 a can, least expensive product tested
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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 | Claim | Soak_observation_1hr | Recipe |
|---|---|---|---|
| 1Liquid Wrench$4 a can, least expensive product tested | claims to dissolve rust and cut through grease | very much like the Kroil, appears absorbed down into the threads or evaporated off; reviewer could not visibly tell if it had dissolved more rust than the Kroil, describing them as looking about the same | not tested |
| 2ATF/Acetone 1:1 homemade mix of synthetic automatic transmission fluid and acetone | not tested | a lot of oily film still left behind (attributed to the ATF), which the reviewer suggests means it would keep working its way into the threads over time | one part acetone to one part synthetic automatic transmission fluid |
| 3Royal Purple Max Film$13 a can | synthetic penetrant lubricant claimed to provide good wear protection, prevent rust and corrosion, and loosen rusted and stuck parts | compared to PB Blaster, more of the product was visibly left on the threads and nut | not tested |
| 4WD-40 | claimed to lubricate, protect from rust, act as a penetrant, and serve as a water displacement product | very clear that a lot of WD-40 was still left behind; the reviewer notes it does not evaporate off as quickly as the other products tested | not tested |
| 5PB Blaster | claimed to be the number one selling penetrant, breaks free rusted and frozen parts, protects against further rust and corrosion, and attacks rust from all angles using capillary action | did not have as much film left behind as the Liquid Wrench or Kroil; described as a lot drier | not tested |
| 6Kroil AeroKroil$15 a can, most expensive product tested | claimed to lubricate, remove rust, clean, and prevent rust; big claim is that it loosens frozen metal parts and can creep into openings as small as one millionth of an inch | most of the product appeared either evaporated off or absorbed down into the threads | not tested |
How it was tested
- visual film/rust observation on the bolt threads after roughly 1 hour of soak time
- breakaway performance after soaking (first four bolts used untreated as a control; 28 rusted grade 8 1/2 inch lug studs, torqued to 100 ft lbs before rusting, used across the six products with two doses of penetrant applied over about 3 hours of soak time); no numeric torque results for this test are stated in the transcript
- comparison against applying heat/torch as a non-penetrant alternative (qualitative only, no numbers given)
“it's very clear that some products are better than others and in this case, the least expensive product at $4 a can, Liquid Wrench, beat all the competition”
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