Cons of Molybdenum?

[FlyPenFly]

It seems that a lot of modern oils have very little or any molybdenum any more as an additive. Notably Castrol Edge, Total Quartz 9000, Motul X-Cess, X-Lite, etc have none. Race oils seem to universally have a huge helping of it and Redline seems to be especially famous for a large dose of Moly for a street oil.

Is there a con to large amounts of moly in an engine that might hurt something? The only research I could find was that moly in some forms can attack copper and that might hurt some parts of some engines.

 

[SuperSalad]

Expense for one.

It has limited synergistic qualities and sometimes relies on those synergies to be fully effective, thereby limiting the additive selection for formulas using it.

New, ashless friction modifier technologies are becoming quite impressive in the past few years that can surpass it without the same limitations.

I think I recall a paper some months back pointing to MoDTC as the cause for some high temperature deposits as well, but I don't recall where I read that.

Those are my own experiences with using Moly in engine oils, but I'm sure each company has their own reasons.

 

[aquariuscsm]

From what I've read,moly is very expensive and some oil co's are using cheaper additives instead of moly that will still do the job adequately.

 

[Rand]

Depends on the type and formulation

The main drawbacks as mentioned are cost and possibly deposits in some engines.

There are also several types IIRC the one M1 uses requires about 1/3 of the amount for a similar benefit compared to the type of moly others use.

 

[Gokhan]

I am a big fan of trinuclear moly but it's hard to tell which oil actually has it. It's made by Infineum of ExxonMobil and Shell.

Moly has no major drawbacks but like most AW/EP/FM/AO additives, it works against detergents and makes cleaning more difficult. Also, there are many AW/EP/FM/AO out there these days and you need to choose a good synergistic combination with the right amounts of ingredients that may or may not have moly.

 

[JHogan]

What does everybody think about MOS2 from liqui moly? Is there a benefit to it?

 

[steve20]

I am a huge moly fan-----> in the right applications:
IMO, specifically OPE & higher mileage engines.
I have never seen any positive results though, in engines with less than 60 K miles. In higher mileage engines quieter valvetrains and much smoother operation at the engine lugging point, say 1300 rpm in 6th gear driving maybe 60 mph---before moly add, considerable unpleasurable vibrations throughtout the drivetrain. Add moly, and became very smooth at those rpm points---I used this only as an example, as I do not intentionally lug the engine.
In many OPE engines, I've seen an engine visibly smoke add moly >> no visible blue oil smoke- except on sudden full acceleration. In other OPe which just consumed oil, oil consumption after moly was eliminated.
I would not use moly in a turbo motor for fear of deposits at the turbo bearing & shaft
Steve

 

[SonofJoe]

Some of the nitrogen-based Moly's (di-thio carbamates and such) can be horrible on Viton elastomer seal compatibility at high concentrations.

It's an old story but I know one major oil company ran a hugely expensive engine test program and left the seals testing till last, only to see the seals die horribly because of Moly. Oh how we laughed!

 

[FlyPenFly]

Originally Posted By: JHogan
What does everybody think about MOS2 from liqui moly? Is there a benefit to it?


Yeah, one of the few additives like Ceratec that are widely known to have an effect.

 

[kschachn]

Originally Posted By: FlyPenFly
Originally Posted By: JHogan
What does everybody think about MOS2 from liqui moly? Is there a benefit to it?

Yeah, one of the few additives like Ceratec that are widely known to have an effect.


Widely known only through anecdotal testimonials however. I've never seen any sort of laboratory test that the additive "does" anything, have you?

 

[Olas]

Originally Posted By: kschachn
Originally Posted By: FlyPenFly
Originally Posted By: JHogan
What does everybody think about MOS2 from liqui moly? Is there a benefit to it?

Yeah, one of the few additives like Ceratec that are widely known to have an effect.


Widely known only through anecdotal testimonials however. I've never seen any sort of laboratory test that the additive "does" anything, have you?


You've never seen tests on the abilities of MOS2 in engine oil?
Lots of good info here http://bfy.tw/BN7d

 

[kschachn]

Originally Posted By: Olas
You've never seen tests on the abilities of MOS2 in engine oil?
Lots of good info here http://bfy.tw/BN7d


And all those results are specific to the Liqui-Moly additive?

I guess somehow I'm still missing the lab tests for that product.

 

[PimTac]

In a thread regarding Ceratec, I brought up the question of how Ceratec reacts or works with the many coatings like DLC for example that the automotive industry is using. The same question could be applied to moly. Does moly work in the same fashion with coatings present?

On a side note, I notice that oil manufacturers seem to be reducing moly amounts in their oils and yes I know that the tri-nuclear form takes less to accomplish the task. The trend is towards newer unseen friction modifiers which do not show on analysis reports thus confusing or irritating BITOGers.

 

[Jetronic]

Originally Posted By: kschachn
Originally Posted By: Olas
You've never seen tests on the abilities of MOS2 in engine oil?
Lots of good info here http://bfy.tw/BN7d


And all those results are specific to the Liqui-Moly additive?

I guess somehow I'm still missing the lab tests for that product.


https://books.google.be/books?id=cwWgbmL...ing&f=false

https://books.google.be/books?id=_wVoTz1...ing&f=false

https://books.google.be/books?id=m4-DUwO...w4A&cad=rja

https://books.google.be/books?id=VffksOI...ing&f=false

 

[BrocLuno]

To me, the question is always how effective it is with the add pak in the oil at hand... I'm sure they fight quite often...

 

[Jetronic]

from what the links above said they don't actually fight. The MoS2 seems to take the back seat unless there's no surfactant in place. You might not see the full benefit (or any) if you have a quality addpack, but that quality can change depending on time or conditions.

What it does do is help in maintaining a suitable MOFT, by increasing the apparent viscosity in extreme heat.

Not necessary in most engines, but not detrimental either.

 

[kschachn]

Originally Posted By: Jetronic
from what the links above said they don't actually fight. The MoS2 seems to take the back seat unless there's no surfactant in place. You might not see the full benefit (or any) if you have a quality addpack, but that quality can change depending on time or conditions.

What it does do is help in maintaining a suitable MOFT, by increasing the apparent viscosity in extreme heat.

Not necessary in most engines, but not detrimental either.


Once again nothing specific to the actual LIqui-Moly additive. How do you know the exact substances in those links are what are in the Liqui-Moly additive and in the same concentrations? How do I know that any of the results described in those links translate to what I can purchase from Liqui-Moly?

Note that Liqui-Moly makes few and fairly vague claims about their additive, just like other aftermarket additive companies do. No actual test results on their websites of tests that surely they performed on their own products, right? It gets back to this notion often repeated here that Liqui-Moly is "one of the few actually useful additives" or however it is phrased. Why do people think that when there is nothing that ties the actual Liqui-Moly product to anything?

And as you mention, how do I know it does anything beneficial in a fully formulated motor oil?

 

[Jetronic]

I'm not advocating the use either... but I'm also not condemning it.

 

[Shannow]

The tribofilms that moly produces always (from my reading) has MoS2 in it, as the final decomposition product of the moly containing additive.

MoDtc et all aren't the constituents of the tribofilm, but carry it there to be converted into MoS2.

Does that make MoS2 a useful additive in fully formulated engine oils ?

I can't say one way or the other....BUT if an oil was formulated with a bunch of different Zn and Mo species, or partial breakdown compounds, then I'm positive that tribofilms would form more quickly, and be more robust.