AMSOIL Independent Test: Don’t Just Take My Word for It
Real split-sample data from owners who sent the same oil draw to both AMSOIL’s lab and independent Blackstone Labs, plus how to run this test yourself. US & Canada, 2026.
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By Alan Williams, AMSOIL Direct Jobber #1243776 · Tomball, TX · 225-441-6397
20+ years selling this product means my word alone shouldn’t be enough, so this page skips my opinion and goes straight to owner-submitted lab data instead.
Last updated 2026. Reviewed against publicly shared used oil analysis (UOA) reports from independent owner forums.
On This Page
Quick Answer
Owners across multiple forums have run the exact test you’d want to see: splitting a single oil sample and sending it to both AMSOIL’s own lab (Oil Analyzers Inc.) and the fully independent Blackstone Laboratories at the same time. The results across these owner-submitted comparisons are broadly consistent between the two labs, with some normal variance in exact numbers, which is a genuinely reassuring signal since it isn’t AMSOIL grading its own homework in isolation.
This isn’t a curated marketing test. These are real forum threads from AMSOIL customers who were openly skeptical of AMSOIL’s own lab and wanted independent confirmation, exactly the audience this page is written for.
Addressing the Obvious Concern
The Obvious Bias Question, Addressed Directly
AMSOIL’s oil analysis program uses Oil Analyzers Inc. (OAI), a lab with a financial relationship to AMSOIL. It’s a completely fair question to ask whether that relationship could favor AMSOIL’s own oil in the results, and it’s a question that’s been raised repeatedly on independent owner forums like BobIsTheOilGuy and various brand-specific truck and car forums for years.
Rather than take AMSOIL’s answer to that question, or mine, the most useful evidence comes from owners who bypassed the question entirely by testing both labs against the exact same oil sample.
Real Owner Data
What Split-Sample Owner Tests Actually Show
Across multiple independently posted forum threads, owners have drawn a single oil sample, split it, and sent one half to AMSOIL’s OAI lab and the other to independent Blackstone Labs, then posted both reports side by side for the community to compare:
- A Ford Powerstroke diesel owner tested samples taken one minute apart from the same drain valve. Both labs returned similar results overall, with some normal variance, OAI’s report actually rated the oil slightly better on some measures, Blackstone slightly better on others, no dramatic bias in either direction.
- A Honda Gold Wing owner ran the same comparison and found “both companies show high value for the same items, but the values are a little different,” a pattern consistent with normal lab-to-lab measurement variance rather than systematic bias.
- A RAM TRX owner compared AMSOIL’s lab against Blackstone and reported “reasonably similar results” between the two, with AMSOIL’s lab noted as faster in turnaround.
None of these are AMSOIL-published tests, they’re independently posted by AMSOIL customers on unaffiliated forums specifically because they wanted a bias check.
One Real Report in Full
A Real 13,000-Mile Blackstone Report
One Honda Insight owner ran AMSOIL Signature Series 0W-20 with an AMSOIL filter for roughly two years and 13,000 miles, well past a conventional interval, then sent a sample directly to independent Blackstone Labs, with no AMSOIL involvement in the testing. The results:
| TBN (acid-neutralizing reserve) | 1.8, above Blackstone’s “should be” minimum of >1.0 |
| Viscosity at 100°C | 9.3 cSt, within Blackstone’s expected 6.0-9.7 range |
| Fuel dilution | Under 0.5%, well below the 2.0% caution threshold |
| Wear metals (iron, copper, aluminum) | In line with or below Blackstone’s universal averages for comparable mileage |
Blackstone’s own comment on the report noted the oil still looked serviceable and suggested the owner could push toward 15,000 miles on the next interval, independent, third-party confirmation that the oil was still functioning well past a conventional 5,000-mile change.
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Verify It Yourself
How to Run This Test Yourself
- Order two sample kits, one from AMSOIL’s oil analysis program and one from Blackstone Laboratories (blackstone-labs.com).
- Draw your sample and split it into both kits at the same time, ideally within a minute or two of each other, from the same drain valve or dipstick tube.
- Send both in without noting your driving conditions if you want an unbiased read, several forum posters found it useful to see whether each lab’s independent interpretation lined up.
- Compare the reports for TBN, viscosity, wear metals, and contamination. Expect some normal variance between labs, not identical numbers, but no red flags if AMSOIL’s numbers are dramatically better than Blackstone’s on your specific sample.
Costs run roughly $25-45 per lab depending on which add-on tests (like TBN) you include, a reasonable price for genuine independent peace of mind on your own vehicle.
Alan’s Take
“I’d be skeptical of AMSOIL’s own lab too if I were in your shoes, so I didn’t build this page around AMSOIL’s data at all. These are other customers’ split-sample tests, posted on forums I don’t run and can’t edit. That’s the whole point of a page titled ‘don’t just take my word for it,’ it shouldn’t actually ask you to.”
Frequently Asked Questions
Is AMSOIL’s own oil analysis lab biased?
AMSOIL’s lab (Oil Analyzers Inc.) has a financial relationship with AMSOIL, a fair concern raised repeatedly on independent forums. Split-sample comparisons by owners testing both AMSOIL’s lab and independent Blackstone Labs simultaneously have generally shown broadly consistent results between the two, without dramatic bias favoring either lab.
What is a split-sample oil analysis test?
Drawing a single oil sample and dividing it between two different labs to compare their independent results against the exact same oil, a common method owners use to check for bias or inconsistency between testing services.
How much does independent oil analysis cost?
Roughly $25-45 per sample depending on the lab and which add-on tests, like TBN, are included. Blackstone Labs and AMSOIL’s own program are both commonly used options.
Did an independent lab confirm AMSOIL’s extended-interval claims?
In at least one publicly shared case, an owner running AMSOIL Signature Series 0W-20 for roughly 13,000 miles and two years had the oil independently tested by Blackstone Labs, which found a TBN of 1.8, well above the minimum threshold.
Verified by Owners, Not Just Marketing
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Disclaimer & affiliate disclosure: Owner-submitted test data referenced here is drawn from publicly posted forum threads on independent, AMSOIL-unaffiliated automotive forums as cited; individual results vary by vehicle, driving conditions, and sample handling, and are not a guarantee of results for any other vehicle. AMSOIL and Blackstone Laboratories are named for identification purposes; this article is not endorsed by either. Lube Oil Sales is an Authorized AMSOIL Independent Dealer (Dealer #1243776). This page contains affiliate links. Last updated: 2026.