What is a "Full Synthetic" Oil?

Status
Not open for further replies.

Shel_B

Site Donor 2023
Joined
Aug 7, 2020
Messages
5,857
I see the term "Full Synthetic" bandied about the forum frequently. Is someone able to tell me what it means? Is there a definition for the term? In Germany, I believe, full synthetic has a specific definition and the oil must conform to a certain standard. I don't think that's the case here in the States, or even Canada or Mexico.
 
That term will have different meanings depending upon what country you're in. Some are very strict; others very lax. (The US has no official stanard for the term, so just realize that anything you read will be "fungible" in its meaning).

After 4 years here, and over 5k posts, you really can't figure this out for yourself ????
 
You didn’t like the answers the last times you asked?


 
You didn’t like the answers the last times you asked?
I don't remember asking before, it was more than four years ago, but thanks for reminding me of my fallibility. It never fails to amaze me at how good you are at digging up old threads and comments, an attribute truly to be admired.

If I've not said it before, although I may have, I suffered a minor brain imjury in a motorcycle accident many years ago, and my memory has suffered. I forget some things, and sometimes repeat myself. It's gotten quite a bit better over the years, but I've gotta work at it.

After 4 years here, and over 5k posts, you really can't figure this out for yourself ????

It crossed my mind, I thought I'd ask. Sometimes my memory is not so good.
 
Last edited:
An in-depth article on this subject matter was written by John Rowland. He explained all of the intricacies of the various base oil groups in order to help you distinguish between fact and fiction. Here is an excerpt from his teachings:


The Synthetic Myth

What do we mean by the word “synthetic”? Once, it meant the “brick by brick” chemical building of a designer oil, but the waters have been muddied by a court case that took place in the USA a few years ago, where the right to call heavily-modified mineral oil synthetic, was won. This was the answer to the ad-man’s dream; the chance to use that sexy word “synthetic” on the can, without spending much extra on the contents! Most lower cost “synthetic” or “semi-synthetic” oils use these hydrocracked mineral oils. They do have some advantages, particularly in commercial diesel lubricants, but their value in performance engines is marginal.

TRUE synthetics are expensive (about 6 times more than top quality mineral oils). Looked at non-basically there are three broad catagories, each containing dozens of types and viscosity grades:-

PIBs (Polyisobutanes)

These are occasionally used as thickeners in motor oils and gear oils, but their main application is to suppress smoke in 2-strokes.

The two important ones are:

Esters

All jet engines are lubricated with synthetic esters, and have been for 50 years, but these expensive fluids only started to appear in petrol engine oils about 20 years ago. Thanks to their aviation origins, the types suitable for lubricants (esters also appear in perfumes; they are different!) work well from 50 degC to 200 degC, and they have a useful extra trick.

Due to their structure, ester molecules are “polar”; they stick to metal surfaces using electrostatic forces. This means that a protective layer is there at all times, even during that crucial start-up period. This helps to protect cams, gears, piston rings and valve train components, where lubrication is “boundary” rather than “hydrodynamic”, i.e. a very thin non-pressure fed film has to hold the surface apart. Even crank bearings benefit at starts, stops or when extreme shock loads upset the “hydrodynamic” film. (Are you listening, all you rally drivers and off road fanatics?)

Synthetic Hydrocarbons or POA’s (Poly Alpha Olefins)

These are, in effect, very precisely made equivalents to the most desirable mineral oil molecules. As with esters, they work very well at low temperatures, and equally well when the heat is on, if protected by anti-oxidants. The difference is, they are inert, and not polar. In fact, on their own they are hopeless “boundary” lubricants, with LESS load carrying ability than a mineral oil. They depend entirely on the correct chemical enhancements.
 
An in-depth article on this subject matter was written by John Rowland. He explained all of the intricacies of the various base oil groups in order to help you distinguish between fact and fiction. Here is an excerpt from his teachings:
Thanks for posting that. Although the subject has been discussed before, the article adds a few things to this discussion. It was posted on BITOG some time back, which I discovered while searching for the article. Here's a link in case some newer folks, or those less knowledgeable, care to read it. I'd not seen it before ...

 
Last edited:
OK, let's answer the other part of the question. Not "what is a synthetic base oil?" but "what is a full synthetic oil?"

A full-synthetic oil is one where all of the base oil used to blend it is of a synthetic nature (whatever that means wherever you are). A motor oil is blended using base oils and additives. The "full synthetic" part only refers to the base oils used.

However, even an oil made with only PAO or ester or whatever is still not 100% synthetic, because there is a strong likelihood that the additives contain a mineral-type base oil. Additives are rarely neat, they are almost always cut with base oil for processing and handling purposes and this base oil is almost always of a non-synthetic type.
 
OK, let's answer the other part of the question. Not "what is a synthetic base oil?" but "what is a full synthetic oil?"

A full-synthetic oil is one where all of the base oil used to blend it is of a synthetic nature (whatever that means wherever you are). A motor oil is blended using base oils and additives. The "full synthetic" part only refers to the base oils used.

However, even an oil made with only PAO or ester or whatever is still not 100% synthetic, because there is a strong likelihood that the additives contain a mineral-type base oil. Additives are rarely neat, they are almost always cut with base oil for processing and handling purposes and this base oil is almost always of a non-synthetic type.
They are marketing weasel words, weasley. ;)
 
There is no legally recognized definition of "synthetic oil". At best, "synthetic oil" is oil made of molecules not normally existing in nature. This can include molecules modified by man.

So, a "full synthetic" would exclude blends of conventional and "synthetic" oils.
 
It's so screwed up that brands sometimes even use misleading labels such as "Synthetic Technology", the average joe thinks, oh! that must be Full Synthetic then, nope, it's a blend.

Motul in fact was fined, quite heavily in Germany for these kinds of misleading labels on their Syn-Blends, or Hydroccracked Oils.
When in Germany it must be clearly labeled as either Mineral (Conventional), Teilsyntetisch ( Part-Synthetic ) , HC-Synthese ( Hydrocracked a.k.a Group 3 ), or Vollsyntetisch ( Fully Synthetic ), which means if i'm not wrong that it is at least 70% Group 4 or 5 ( PAO,PAG,AN,Ester etc etc. )

Everywhere else, it's basically the wild west, sadly.
 
Status
Not open for further replies.
Back
Top