PAO and Hydrocraked can lead to more varnish and deposits?

[Drew7a]

https://www.machinerylubrication.com/Read/268/oil-sludge-varnish

The article above seems to indicate that PAO and Hydrocraked oils could lead to more varnish and sludge.

 

[Brian123]

It seems like the article is talking about Machines in Industry!

 

[wpod]

The best oils are a base oil blend , GP4 and GP3 have low natural solvency .

 

[Jetronic]

Yes it's a solvency thing. Dispersants in engine oils should mitigate the lesser solvency of the base oils. Not so much in industrial oils possibly.

 

[Drew7a]

I have seen a lot of posts wanting oils with higher PAO content or debating which basetocks are better but in reality it is all about the final blended product that matters and what approvals it meets.

 

[OVERKILL]

I have seen a lot of posts wanting oils with higher PAO content or debating which basetocks are better but in reality it is all about the final blended product that matters and what approvals it meets.

The higher the level of refinement (with a hydrocracked base) the more "dry" it is, which means as you go from Group II -> II+ -> III -> III+ you get poorer and poorer solvency. But this also improves oxidation resistance and cold temperature performance, so it's a trade-off. This makes it more and more similar to PAO, which has extremely poor solvency, but excellent oxidation resistance and untouchable cold temperature performance.

So, the solution is to mix these bases with ones that have higher solvency like esters or AN's. You don't need a ton, and this is indeed part of producing a fully formulated lubricant and a properly blended product that uses either of these bases will be designed around accommodating their weaknesses while capitalizing on their strengths.

I highly recommend this paper from the STLE on AN's, which I linked in my thread on Dr. Rudnick (who does the formulation for HPL):
https://www.stle.org/images/pdf/STL...halenes for High Temperature Applications.pdf

It shows examples of major improvements in handling high heat with not only PAO, but also with POE.

 

[userfriendly]

Three engine oils that come to mind are Havoline Super Plus SAE 30 & 40 and Chevron Delo 100 SAE 40. All group I for cleaning up old engines.

 

[userfriendly]

Yes it's a solvency thing. Dispersants in engine oils should mitigate the lesser solvency of the base oils. Not so much in industrial oils possibly.

I don't think it would be wise to mix the two in industrial applications.

 

[BMWTurboDzl]

https://www.machinerylubrication.com/Read/268/oil-sludge-varnish

The article above seems to indicate that PAO and Hydrocraked oils could lead to more varnish and sludge.

As I understand this has always been the case with PAO but it occurs much further into the oil change interval compared to mineral oils. Gr3+ oils also exhibit this tendency but it doesn't surprise me as they're much closer to PAO.

This is why correctly formulated oils are important in order to take advantage of the drain interval.

 

[Hermann]

OMG, More Varnish, when will it end , the end is nigh.

 

[BMWTurboDzl]

The higher the level of refinement (with a hydrocracked base) the more "dry" it is, which means as you go from Group II -> II+ -> III -> III+ you get poorer and poorer solvency. But this also improves oxidation resistance and cold temperature performance, so it's a trade-off. This makes it more and more similar to PAO, which has extremely poor solvency, but excellent oxidation resistance and untouchable cold temperature performance.

So, the solution is to mix these bases with ones that have higher solvency like esters or AN's. You don't need a ton, and this is indeed part of producing a fully formulated lubricant and a properly blended product that uses either of these bases will be designed around accommodating their weaknesses while capitalizing on their strengths.

I highly recommend this paper from the STLE on AN's, which I linked in my thread on Dr. Rudnick (who does the formulation for HPL):
https://www.stle.org/images/pdf/STL...halenes for High Temperature Applications.pdf

It shows examples of major improvements in handling high heat with not only PAO, but also with POE.

Pg 28 of that presentation in particular gives a good look at how ANs keep varnish inducing material from attaching to surfaces and remain in suspension.

 

[DirectRejection]

I will never ever use oil additives again. Dr. Rudnick gets it just right.

 

[BigTimeTA]

https://www.machinerylubrication.com/Read/268/oil-sludge-varnish

The article above seems to indicate that PAO and Hydrocraked oils could lead to more varnish and sludge.

They are referring to industrial applications where high temperatures above 270 F is the norm where even PAO struggle to hold up. Typically there's a lot of lower cost-effective base stocks that wouldn't be as problematic as PAO in an industrial application like PAGs, Diesters, Polyolesters and Silicones, but seals MUST designed to be compatible with PAGs in particular. Usually you won't find significant deposits or varnish problems from PAO in a passenger car application if any at all. Different applications and different problems in short.

 

[SubieRubyRoo]

Chevron:
Varnish is triggered in various ways. In general, the cycle of varnish starts with something that upsets the stability of the lubricant, usually a thermal event such as excessive heat. This causes the oil to start degrading and impurities to start forming. For a long time, those impurities stay dissolved in the oil and don’t cause any harm. As more and more accumulate, however, they begin to stick together, forming insoluble, suspended submicron particles. Ultimately, these particles become polar, or electrically attracted to metal surfaces. When they start sticking to those surfaces, they become varnish.



Cross-contamination of oils with incompatible additives can also trigger the varnish cycle. If an operator introduces a new oil with a different additive formulation from the existing oil, the additives can react with each other, which upsets the lubricant and starts the process of degradation that ultimately leads to varnish.

Hoping some of our oil experts (@High Performance Lubricants or @MolaKule or others) could comment specifically on the 2nd paragraph here… are there indicators of what would lead to this phenomenon so it can be avoided? Is it an elemental issue or is it an additive issue?

Meaning, although an Oil Analysis gives essentially a top-level view of an oil, is this something that can be predicted, or does the Chevron article exaggerate the risks of this occurring in an ICE? I understand other applications may exhibit a higher incidence. Thanks!

 

[nthach]

I’ve always thought, at least in cars cheaper base oils with lower NOACK and olefin/MMA VIIs cause varnish to form. Doesn’t PAO, as well as “synthetic” GIII base stock have less polarity to metal as well?

I thought the reason Red Line and HPL use esters in their formulations was high-temp cleanliness and to minimize VII use?

 

[Tom NJ]

PAOs are non-polar and therefore have limited ability to solubilize or suspend oil degradation by-products, which in time can lead to varnish/carbon deposits under some conditions. That said, we do not lubricate with PAO - we lubricate with lubricants. Lubricants contain other ingredients that provide the solubility and dispersion properties needed for proper lubrication. The base oils are just one part of the whole.

 

[MolaKule]

Hoping some of our oil experts (@High Performance Lubricants or @MolaKule or others) could comment specifically on the 2nd paragraph here… are there indicators of what would lead to this phenomenon so it can be avoided? Is it an elemental issue or is it an additive issue?

Meaning, although an Oil Analysis gives essentially a top-level view of an oil, is this something that can be predicted, or does the Chevron article exaggerate the risks of this occurring in an ICE? I understand other applications may exhibit a higher incidence. Thanks!

1. The article was copyrighted in 2002.
2. In terms of severe service and industrial use, the article has some merit.
3. In terms of daily driver service, the article does go over the top somewhat,
4. Since the article was written (point 1), newer cleaning agents have been incorporated in the latest engine oils.

Modern formulated oils don't depend on one base oil and the DI additive package contains chemistry to assist the base oils in doing what they cannot do alone.

 

[sk_pete]

It seems like the article is talking about Machines in Industry!

car is not a machine ?

 

[MolaKule]

car is not a machine ?

Machines in Industry would be, expressing it differently, Industrial Machines.
Automobiles would not qualify under that heading.

 

[ZeeOSix]

Machines in Industry would be, expressing it differently, Industrial Machines.
Automobiles would not qualify under that heading.

This is a snip-it from the Machinery Lubrication article. Many of those factors can be seen in passenger car/truck engines.