Ester or PAO

[Toyota18]

Which oil you guys preffer? Ester/PAO or 100%PAO engine oil's?

 

[Al]

No PAO's are 100%. Need some ester to avoid seal damage. Ester's are a better lubricant (probably) with higher temps, lower pour points, and more protection. There are several articles on this ..try a search for "PAO" or "Ester"

 

[Toyota18]

Castrol said their Castrol Formula R 0w-40 is 100% PAO synthetic.I also heard PAO synthetic need either group3 or ester for seal swell.

 

[bulwnkl]

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Originally posted by Toyota18:
Castrol said their Castrol Formula R 0w-40 is 100% PAO synthetic.I also heard PAO synthetic need either group3 or ester for seal swell.

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Usually when any oil company says "100% whatever," they are referring to base stocks. However, additives are blended in carrier oils which are not the same as the base stock. Some esters are there as a seal swell additive. Therefore, you'll see something like Castrol's claim but the oil will still have some ester in it.

Neither group III oils nor PAOs will cause seal swell; they need some ester to make that happen.

 

[ericgl]

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Originally posted by bulwnkl:

Neither group III oils nor PAOs will cause seal swell; they need some ester to make that happen.

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Additionally, pure G-IIIs or PAOs will not hold the additives in suspension.

 

[MolaKule]

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Additionally, pure G-IIIs or PAOs will not hold the additives in suspension.

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Additives are supplied as a solution of Group I/II/III process oils and ester.

The dispersant component in lubes is usually the additive that really increases the solvency of PAO and GIII.

 

[1911]

quote:

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Originally posted by MolaKule:

quote:

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Additionally, pure G-IIIs or PAOs will not hold the additives in suspension.

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Additives are supplied as a solution of Group I/II/III process oils and ester.

The dispersant component in lubes is usually the additive that really increases the solvency of PAO and GIII.

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Thanks Molekule,

Does this mean that even Mobil 1 has at least a small bit of refined "dino" in it to help carry the additives. OR, can the additive pack in these oils be carried by a special mix of esters alone? The reason I ask is because Mobil has seemed to indicate (at least since the time of the tri-sythetic version) that it's syn lubes were 100% synthetic including the additives carriers and all.

Thanks,
1911

 

[buster]

The majors have found that PAO with some esters are the best combination. Shell and Mobil have stated how 100% ester basestocks actually show increased wear due to additives competing with the surface.

I personally believe that it's not just cost as to why most high end synthetics are blends of Group III/IV/V basestocks. Even Elf's F1 oils are blends of PAO/III and V basestocks. These companies make esters and have chosen not to use them solely by themselves.

 

[buster]

More on the subject:
http://www.migweb.co.uk/forums/archive/index.php/t-139943.html

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As there seem to be many oil discussions here but no real technical explanations of what constitutes a good oil, I thought that those interested would benefit from reading this. It's very technical because it's written by an R&D Chemist with 40 years experience and not a sales pitch extolling the virtues of a brand of oil. It's a factual and interesting read!

Building a good oil.

It is impossible to make a good 5w-40 or even 10w-40, using only mineral oil. The base oil is so thin, it just evaporates away at the high temperatures found in a powerful engine that is being used seriously. Although there are chemical compounds in there to prevent oil breakdown by oxygen in the atmosphere (oxidation) they cannot adequately protect vulnerable mineral oil at the 130 degC plus sump temperatures found in a hard working turbocharged or re-mapped engine.

The answer to this is synthetics. They are built up from simple chemical units, brick by brick so as to speak; to make an architect designed oil with properties to suit the demands of a modern engine.

The synthetic myth

The word “synthetic” once meant the brick by brick chemical building of a designer oil but the waters were muddied by a court case that took place in the USA some years ago. The outcome was that the right to call heavily modified mineral oil “synthetic” was won. This was the marketing executives dream; the chance to use the word “synthetic” on a can of oil 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 and in basic terms there are three broad catagories, each containing many types and viscocity grades:-

PIB’s (Polyisobutanes)

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

The TWO important ones are:

ESTERS

All jet engines are lubricated with synthetic “esters” and have been for more than 50 years but these expensive fluids only started to appear in petrol engine oils around 20 years ago.
Thanks to their aviation origins, the types suitable for lubricants work well from
-50 degC to 200 degC, and they have an added benefit. 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 surfaces apart.
Even crank bearings benefit at starts, stops, or when extreme shock loads upset the “hydrodynamic” film.

Synthetic Hydrocarbons or PAO’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 at high temperatures, 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.

It is a fact that “PAO’s” work best in combination with “esters”. The “esters” assist load carrying, reduce friction and cut down seal drag and wear, whilst the “PAO’s” act as solvents for the multigrade polymers and a large assortment of special compounds that act as dispersants, detergents, anti-wear and anti-oxidant agents, and foam suppressants.
Both are very good at resisting high-temperature evaporation, and the “esters” in particular will never carbonise in turbo bearings even when provoked by anti-lag systems.

So, in conclusion, Ester gives the best protection and Ester/PAO combinations have great benefits because they work well together. They are more expensive but worth it if you wish to do the best for your engine.

Cheers
Simon

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[G-MAN]

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Originally posted by buster:
More on the subject:
http://www.migweb.co.uk/forums/archive/index.php/t-139943.html

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The “esters” assist load carrying, reduce friction and cut down seal drag and wear, whilst the “PAO’s” act as solvents for the multigrade polymers and a large assortment of special compounds that act as dispersants, detergents, anti-wear and anti-oxidant agents, and foam suppressants.

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Uh...wrong. PAOs are horrible solvents. I think this guy is out to lunch on most of what he wrote.

 

[MGBV8]

The above info is from Silkolene Chemist

http://www.silkoleneoil.com/techtips.htm

 

[Nickdfresh]

quote:

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Originally posted by buster:
More on the subject:
http://www.migweb.co.uk/forums/archive/index.php/t-139943.html

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Excellent article Buster, thanks!

Cheers yourself!

 

[buster]

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In fact, on their own they are hopeless 'boundary' lubricants, with less load carrying ability than mineral oil. They depend entirely on the correct chemical enhancements.

In fact PAOs work best in combination with esters. The esters assist load carrying, reduce friction, and cut down seal drag and wear, whilst the PAOs act as solvents for the multigrade polymers and a large assortment of special compounds that act as dispersants, detergents, anti-wear and anti-oxidant agents, and foam suppressants. Both are very good at resisting high-temperature evaporation, and the esters in particular will never carbonise in turbo bearings even when provoked by anti-lag systems.

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[Idrinkmotoroil]

when synthetics first came onto the market didn't they all have the same type of claim on the back of the bottles, something like 100% synthetic, then in small print it would state exclusive of base fluids or something like that. So there is always a component that is not 100% synthetic.

 

[G-MAN]

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Originally posted by Idrinkmotoroil:
when synthetics first came onto the market didn't they all have the same type of claim on the back of the bottles, something like 100% synthetic, then in small print it would state exclusive of base fluids or something like that. So there is always a component that is not 100% synthetic.

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The wording was "Exclusive of additive carrier oil." Add packs used to be "carried" in Group I mineral oil.

 

[ShortBuSX]

I find all this or this is contradictory...which is it? I mean, is a mix of ester and PAO good or bad? From what the link suggests is that Terry has warned not to mix the two.

 

[MolaKule]

G-MANII is correct, Simon is off-base.

PAO's have lousy solvency and esters are used as solvents. either in a virgin form or from other additives.

A little insight, anytime you see an MSDS which states "diisodecyl ester," that is a di-ester used for seal swell, pour point depression, and as a friction reducer. It also aids in solvency, but dispersants usually help with that.

 

[labman]

Mineral oil or PAO's are solvents for the viscosity index improvers. Poor solvents, when cold, not thickening the oil, and better when hot, uncoiling the polymers and countering the effect of the heat on the base oil. After all, even more of them must stay in solution in a straight chain mineral oil. The biggest advantage of a PAO is that they require less of the sludge forming additives. Chemically they are very similar to dino and have similar solvency.

 

[MolaKule]

Sorry to disagree, but dispersants and esters are the main solvents for PCMO's that contain majority PAO base oils.

In a PAO you cannot get anything to mix with it unless you add a diester or dispersant.

Without an ester or dispersant for solvency, the the PAO just froth's into a white mess.

Many VII's today come in a VII/dispersant add package. This type of multifunctional additive is okay for PCMO's but not for diesel oils.

 

[labman]

If the polymers don't dissolve in the base oil when hot, they can't increase the viscosity. Other additives may need other materials to keep them in solution or suspension.