Petroleum Oil Cross-Dresses as Synthetic

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In the lubrication industry, “petroleum cross-dressing” started in 1997 when Castrol Syntec decided to put a petroleum base-stock in the bottle but still call it a “full synthetic”.  Of course it wasn’t, and at that time in nearly any other country in Western Civilization it was still considered false advertising for Group III hydrocracked petroleum oil to “cross-dress” as a synthetic.  But in the U.S. this unethical fraud became legally OK because the petroleum companies flexed their muscles, and talked government officials into approving a definition that supported their business model. Since then, the expanded definition has been spread to other countries.

Anybody remember Crocodile Dundee in the New York City bar when he couldn’t believe the story that the “woman” was really a man?  There’s a lesson there that has been duplicated for a lineup of “synthetic” engine oils: a bold and closeup “test-grab” study of ten synthetic engine oils reveals what “real” synthetic oils are like.

The classic article below does a great job of explaining how we got here.

Fortunately, it’s still a free America at the moment.  If you don’t like the parade of cross-dressing petroleum oils, it’s a good idea to vote with your dollars – especially since vastly superior synthetic lubricants are a vastly superior choice that saves you money. (Here’s how to pick the best engine oil.  And no, AMSOIL synthetic oils don’t cause gasket leaks or oil-seal leaks.)

Synthetic Motor Oil Gets All New Semantics

(first published in Nov., 2000 issue of Car and Driver by Patrick Bedard, we have added helpful clarity in [brackets] and after the article’s end)

Now that the meaning of “is” has gotten so slippery you need to grab it with both hands, we’d better keep an eye on longer words, too.

One’s already got so squirmy on us – “synthetic,” as in synthetic motor oil.

Most guys know two things about synthetic oils. First, the price is three to four times that of conventional oils. Second, they’re not real oil, not made from crude.

News flash: Scratch that second part. Now motor oils derived from crude may be labeled “synthetic.” But they still cost over four bucks a quart.

Bait and switch? That’s the obvious conclusion. Except in this case the advertising ethics people have given their approval.

Here’s what happened, according to a detailed account published in the trade magazine Lubricants World. Late in 1997, Castrol changed the formula of its Syntec “full synthetic motor oil”, eliminating the polyalphaolefin (PAO) base stock (that’s the “synthetic” part, which makes up about 70% by volume of what’s in the bottle) and replacing it with a “hydroisomerized” petroleum base stock.

Mobil Oil Corporation, maker of Mobil 1, “Worlds Leading Synthetic Motor Oil,” said no fair and took its complaint to the National Advertising Division (NAD) of the Council of Better Business Bureaus. NAD often arbitrates between feuding advertisers on their conflicting claims.AMSOIL is devoted to protection

The notion behind synthetic motor oils as we’ve known them is an elegant one. Instead of relying on the cocktail of hydrocarbons contained in crude oil, why not go into the laboratory and build the perfect base stock from scratch, molecule by molecule, and build it till it gets 10-carbon molecules, then combines three of those to form PAO. The result is a fluid more stable than the usual base oils derived from crude. It keeps flowing at low temperatures. It’s more resistant to boiling off, and more resistant to oxidation, which causes thickening with prolonged exposure to high temperatures.

Still, there’s more than one road to the point B of improved stability. Petroleum refiners in recent years have learned how to break apart certain undesirable molecules – wax, for example, which causes thickening of oil at low temperatures- and transform them by chemical reaction into helpful molecules. These new hydroisomerized base oils, in the view of some industry participants provided properties similar to PAO’s but only cost half as much,” Lubricants World reported.

The argument before NAD tiptoed around the obvious – does the consumer get four bucks’ worth of value from each quart of synthetic oil? – and plunged straight into deep semantics. Mobil’s experts said “synthetic” traditionally meant big molecules built up from small ones. Castrol’s side held out for a looser description, defining “synthetic” as “the product of an intended chemical reaction.”

What do unbiased sources say? It turns out that the Society of Automotive Engineers (SAE) and the American Petroleum Institute (API) both have technical standards covering motor oils, and both of these organizations in the ’90’s backed away from their old definitions of “synthetic,” leaving lots of room for new interpretations.

In the end, NAD decided that the evidence constitutes a reasonable basis for the claim that Castrol Syntec, as currently formulated, is a synthetic motor oil, said Lubricants World.

The obvious question now: Has the term “synthetic motor oil” been opened up to the point that it no longer means anything? Maybe. But here’s a better question: Did synthetic ever mean what we thought it meant?

“Great oil” is what most guys think it means. “At that price, it’s gotta be great stuff!”

Okay, but how great? Your cars manual tells what motor oil you should use, and with few exceptions, that description will consist of only two specifications. One is for viscosity, such as 10W-30; and the other is for the API service grade, SJ being the current one for gasoline passenger cars.

The buck-a-quart multi-grades meet these standards, as do the synthetics.

The synthetics, on the back label, claim compliance with more standards, but even if you know what they mean, they seem beside the point for U.S. passenger cars. For example, should you care about diesels if you drive a gasoline burner? API service CF is the oldest of the current specs for light-duty diesels; some synthetics list that one. Synthetics may also list ACEA A1 and B1, which are European specs roughly equivalent to API gasoline and diesel specs. The Europeans grad their oils by level of performance, so that A2 and A3 are tougher specs than A1. Same for diesels. Usually the date of the spec is omitted, but A1-98 is newer than A1-96.

Completely absent is the one performance claim that would have some real meaning for all of us – some indication of longer oil life. [Except for AMSOIL which clearly states 25,000 miles/1-year for its flagship line of Signature synthetic oils.] Automakers hold synthetics to the same oil change intervals as conventional oils. And the oil companies promise even less. “To give added protection and life to your engine, change your oil every 3000 miles.” This same language appears on the back of both Pennzoil Synthetic and conventional oils. Valvoline synthetic makes a similar recommendation. [Commentary: Since 1972 AMSOIL is the ONLY synthetic oil manufacturer in the world to guarantee 25,000 miles or 35,000 mile oil change intervals and utilizing full PAO synthetic technology exclusively – until, as some have surmised, the adding of some Group V and/or Group VI content to the PAO in recent years.]

Synthetics do get one unambiguous endorsement: Corvettes, Porsches, Vipers, and all AMG models from Mercedes-Benz come with Mobil 1 as the factory fill.
AMSOIL provides 75% Better Protection 400x300_75ASL

Most synthetics mention GM 4718M in their list of claims; that’s the unique spec created by General Motors for Corvette oil. It’s a high-temperature requirement that tolerates less oxidation (thickening) and volatility (boil-off) on a standard engine test called Sequence 111E according to engineer Bob Olree of GM Powertrain. [Note: AMSOIL’s Signature oils far surpass GM’s 4718M spec, as well as the latest GM dexos1 Gen 2.]

But don’t expect to learn such details on any label [again, except for AMSOIL which clearly states test results in the back-label of every bottle of, for example, Series 2000 0W-30 and 20W-50 synthetic]. Mobil 1 at least uses straight forward declarative sentences. Most of the others read as though they were written by a lawyer looking for an escape clause. Why else would the following claim be so rubbery? “Pennzoil Synthetic motor oil is recommended for use in all engines requiring ILSACGF-1, GF-2, API SJ, SH, or SG, and in engines requiring oils meeting GM 4718M.” Okay, but does it actually pass those standards?

“Yes” says James Newsom, Pennzoil’s motor-oil product manager.

Castrol Syntec, on its label, “exceeds” every standard it mentions. Hmm. Now that the meaning of “is” is in play, I have to wonder, does Syntec meet those standards as well?

“It does” says Castrol’s Julie Ann Oberg. While I have her on the phone, I ask if there will be a Syntec price reduction now that the lower-cost base stock has been substituted for the old synthetic. She says no.

End of article.

Now, after reading that why would anybody in their right mind want to spend their hard-earned money on Castrol Syntec, Penzoil Synthetic, Valvoline Synthetic or any of the other “synthetics” when what your getting is not even a true 100% full synthetic? 

Help!  How can I tell the difference between a true high-performance synthetic motor-oil  that’s worth my money, and a glorified petroleum “synthetic”?

Just look on the back product label. If you don’t see “Group IV” (or “Group 4”) and the “synthetic” label either mentions “Group III” base-stocks or no group at all, then the base-stock has at least a significant amount of Group III “hydrocracked” (hydroisomerized) petroleum oil: it will outperform standard petroleum oils, but does not offer extended drain intervals, is usually not as annually cost-effective as AMSOIL oil-changes, and it will NOT reach AMSOIL’s ultra-low wear rates.

Why not skip the hype and deception of these other manufacturers and just use AMSOIL?
Save up to 25 percent and get exclusive offers as an AMSOIL Preferred Customer PLUS exclusive help from a former OEM headquarters senior engineer

Except for the XL series, designed for the quick-change lube shops, AMSOIL uses only 100% full synthetic Group IV/V/VI technology in each and every one of its motor oils, and is the undisputed leader in synthetic engine oil technology as well as the leader in synthetic gear lubes, transmission fluid, greases, two-cycle oil and many other lubricants and hydraulic fluids. Today, virtually every other motor oil manufacturer has recognized the superiority of synthetic lubricants and has followed the AMSOIL lead with introductions of “synthetic” motor oils of their own.

They spend millions of dollars advertising their “new” and “revolutionary” products. No one, however, can match AMSOIL experience and technological know-how.  And no one delivers product performance and value like AMSOIL. Accept no substitutes – AMSOIL is the “First in Synthetics.”


Standardized test data from the most reliable & trusted tests in industry.  Personal experience.  Combine those two, and when they both agree, there is no doubt about the superior performance of AMSOIL products.

We’ve got the data.  Why not combine that data with YOUR personal experience, so that you KNOW the results are as accurate as you made them yourself?  Contact us, and we’ll help.

Sure, you can keep buying the mediocre performance of the famous mainstream brands that fill most store shelves.  But know that when you do, those oils are costing you a lot more money per year than buying the high-performance AMSOIL solution.
Bottom line?  AMSOIL saves you money.

(We save a LOT of time and money with these AMSOIL “secrets”, and thought you’d like to know them, too. Maximize your savings with the 25% discount of a Preferred Customer membership through, and get free automotive engineering support and advice!)


I can boil it down to two key strategies:  changing your whole drivetrain to top-performance long-life synthetic lubricants, and changing your engine air filters and oil filters to modern military/aerospace nanofiber filtration technology.  Many big companies want to keep these modern technologies hidden.  But fortunately the results have been documented so many times, over so many years, that it is easy to investigate and verify.  Consider just a few:

One way to start is by reviewing the recommendations and looking up your vehicle on the vehicle maintenance page.  Or to learn more, a good primer is our Motor Oil and Filtration Guide.  Open this page for more fleet information.  If you get pushback/doubt/ridicule from a skeptical family-member or mechanic, no problem: just send them here.

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UltimateSyntheticOil promotes the AMSOIL Filtration and Lubrication Gold Standards in the United States and Canada If you want to buy AMSOIL Products, visit our vehicle maintenance page, or the AMSOIL On-Line Store or download a clickable pdf e-catalog


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