2018 test11 productsShop Chemicals & Lubricants
Which Penetrating Oils Brand Wins?
A head-to-head test of 11 penetrating oils options with the measured results for each. See how they ranked and watch the full test video. Shoppers cross-shopping kroil penetrating oil, pb blaster penetrating oil and penetrating oil land here for the head to head that settles it.
Ranked first
Royal Purple Max Film
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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 | Salt water spray test (flat metal, 5 applications over 2 hours) | Three-way dip test (water / salt water / hydrogen peroxide-vinegar-salt mix) |
|---|---|---|---|
| 1Royal Purple Max Film | claims to prevent rust and corrosion | no visible rust formation at all; described as a tremendous product for preventing rust, definitely in the top three, probably top two, of all penetrating oils tested (referencing a prior, separate competition video on penetrating ability) | not fazed by any of the three solutions including the harsh hydrogen peroxide-vinegar-salt mix; graded a solid A |
| 2Fluid Film | claims to provide powerful rust and corrosion protection, and to penetrate to free up heavily seized parts | no visible rust formation whatsoever; graded an A+ | excellent protective coating with no visible rust on the bolts; graded an A |
| 3Seafoam Deep Creep | described as a metal surface protector and a carbon and rust inhibitor | very little rust occurred; host notes some rust at the top was likely wash-over from an adjacent untreated surface and was his own testing fault, and that the main treated area showed absolutely no rust; graded an A | a tremendous job overall; only a very small amount of rust on the head of the nut from the hydrogen peroxide-vinegar-salt mix, and absolutely no rust from the salt water solution; graded an A |
| 4WD-40 | not tested | described with marketing language about preventing rust on tractors and large equipment; performed better than the PB Blaster but not nearly as good as several other products; graded a B+ | did pretty good overall; some rust on the threads and a little on the bolt head from the hydrogen peroxide-vinegar-salt mix, some rust starting on the salt water bolt, and only a small amount on the water-only bolt; graded a solid B |
| 5Liquid Wrench | does not claim to prevent rust; host tested it anyway out of curiosity | quite a bit of rust formation; graded a C | very little rust on either the water or salt water bolts; graded a B, described as a decent job despite not being marketed as a rust preventer |
| 6WD-40 Rust Specialist | helps prevent rust and corrosion from reforming | did an okay job, described as very close to CRC Knock'er Loose; graded a B | did okay; quite a bit of rust on the hydrogen peroxide-vinegar-salt mix bolt, some rust starting on the salt water bolt, and a small amount on the water-only bolt; graded a C |
| 7CRC Knock'er Loose | described as lubricating and preventing rust | seemed to do better than Liquid Wrench, though the host notes Liquid Wrench isn't designed to prevent rust; the letter grade itself is garbled in the transcript, which reads 'I give CRC knocker loose at beyond an A through F scale,' most plausibly intending a grade of B, kept close to verbatim and flagged as uncertain rather than asserted with confidence | quite a bit of rust on the hydrogen peroxide-vinegar-salt mix bolt, only a little rust on the salt water bolt; graded a C (the transcript appends a garbled trailing phrase, 'as well as the max,' after this result, left unresolved) |
| 8BG In-Force | an ion-activated penetrating oil that does not claim to remove or prevent rust | almost as good as CRC Knock'er Loose but not quite; more rust formation at the bottom, and the host notes the rust that was visible looked less severe than it actually was, going deeper into the metal than appearance suggested; graded a C | not advertised to prevent rust but did not do too badly; quite a bit of rust on the hydrogen peroxide-vinegar-salt mix bolt but very minimal rust on the salt water and water bolts; graded a C |
| 9PB Blaster | claims to protect against further rust and corrosion | clearly outperformed AeroKroil in a direct side by side comparison shown on camera; the letter grade is garbled in the transcript ('I'd give PB blaster a bebas'), most plausibly intending a grade of B, kept close to verbatim and flagged as uncertain; host notes it is nowhere near as good as Royal Purple, and also had more rust than WD-40, though not a lot along the bottom | did not appear to beat the control on the hydrogen peroxide-vinegar-salt mix bolt, but did better than the control on the salt water and water bolts; graded a C |
| 10AeroKroil | described in the transcript as an oil that prevents rust and is harmless to metal | did not do a very good job; at best rated a C; better than the control but not by much, and better than brake fluid, but the host places it in the bottom two or three products tested; clearly outperformed by PB Blaster in a direct comparison | not much better than the control on the hydrogen peroxide-vinegar-salt mix bolt; about the same as the control on salt water, maybe slightly more rust; did do better than the control in the plain water test; graded an F overall |
| 11Brake fluid DOT 3 | many viewers have commented that DOT 3 brake fluid causes corrosion; host confirms brake fluid is highly corrosive | a tremendous amount of deep corrosion, far worse than even the untreated control; graded an F | worse than using nothing at all; the hydrogen peroxide-vinegar-salt mix bolt showed a large amount of corrosion that appeared to have sped up rusting; the salt water bolt looked about the same as the control; the water-only bolt looked slightly worse than the control; no explicit letter grade given in this second test, but qualitatively worse than the control across all three sub-conditions |
How it was tested
- preparation: 7/16 inch bolts stripped of their zinc/galvanized protective coating using 31 percent hydrochloric acid to expose bare, rust-susceptible steel
- salt water spray corrosion test: each product applied to a piece of flat iron, then 5 applications of a saltwater spray mix over about 2 hours, graded on an A through F scale against an untreated control
- three-way dip test: bolts coated in each product then soaked for 10 minutes each in plain water, a salt water mix, and a hydrogen peroxide, vinegar, and salt mix, dried for about 12 hours, and graded per solution against an untreated control
“I really think that royal purple and fluid film came out on top and a virtual tie followed very closely by seafoam.”
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