What causes detergents to decrease in oil?

Status
Not open for further replies.
Joined
May 5, 2012
Messages
953
Location
Rio Rancho, NM
Hello, quick question! What causes detergents (Boron) to decrease in an engine? Guessing, it's from working harder and doing its job. It was something I noted on a UOA. Ty


Respectfully,

Pajero
 
Originally Posted By: Pajero
Hello, quick question! What causes detergents (Boron) to decrease in an engine? Guessing, it's from working harder and doing its job. It was something I noted on a UOA.

Regardless of what function the "boron" does in the oil, the relative percentage will not change over an OCI unless it is a volatile compound which is escaping from the oil to the atmosphere. Otherwise the parts per million shown in a VOA will be the same in a subsequent UOA (unless you've got transmutation of elements going on which I highly doubt).

This highlights the caution one should use in an oil analysis. When oil in analyzed via an ICP or AA machine, any compounds are broken apart and only the metal ions are measured. It tells you nothing about the structure of the original compounds, only a parts-per-million of certain elements. So even if the original boron compound in question is degraded or decomposed in the engine for some reason (and is rendered inert) the elemental analysis for boron will remain the same. The measurement of that element is independent of whether it is "doing its job" or "working harder" or doing absolutely nothing. Such subjective determinations cannot be made via a UOA.

If you see it decrease of an element in a UOA then either the measurement was within the range of accuracy for the instrument, the instrument is out of calibration or it is part of a volatile compound which escaped from the oil during use. Even if there is an oil leak the relative concentration will remain the same.
 
Originally Posted By: Eddie
Even DAWN liquid detergent gets weak after washing many greasy dishes.

Yes but an elemental analysis of the depleted Dawn liquid would show the exact same composition of elements as the starting liquid (accounting for the additional grease molecules of course). Like I mentioned above the UOA does not measure effectiveness. The elements in the oil at the start are going to be the same as what is measured at the end, unless they are escaping somehow independent of the bulk oil.
 
This also shows why it is misguided to think that an oil mixture can be evaluated via VOA. Take zinc for example, the VOA only shows the concentration of the zinc atom and doesn't tell you anything about the structure of the coordination compounds. Zinc dialkyldithiophosphates are a variety of compounds and unless you know which exact one (or ones) are being used how do you know that the resulting mixture is overall beneficial to the performance of the oil? You don't.

ICP or AA is like trying to evaluate words and letters on shredded documents. Sure you can tell whether the ink was black or blue or red, but trying to divine words and phrases is not possible. On the flip side there are only so many compounds added to oil containing zinc so perhaps you can take an educated guess, but it should be realized that you aren't measuring the zinc compounds via an elemental analysis at all. You really do not know anything about that via a standard UOA or VOA, only that there is zinc present. I could make up an oil sample using an oil soluble zinc compound that would exactly mirror the zinc concentration of some other oil but would be completely ineffective as a motor oil additive.
 
You can get Boron-based anti-wear additives but I doubt if you will find them in many US engine oils.

It's far more likely that the Boron you're seeing on VOAs is from Ashless Dispersant which has been reacted with Boric Acid to improve its seal elastomer compatibility.
 
Originally Posted By: SonofJoe
You can get Boron-based anti-wear additives but I doubt if you will find them in many US engine oils.

It's far more likely that the Boron you're seeing on VOAs is from Ashless Dispersant which has been reacted with Boric Acid to improve its seal elastomer compatibility.

I think from the way I read the question, he's saying that a VOA (for example) showed 800ppm of boron but a subsequent UOA only showed 600. He's asking what caused the difference and whether the boron was somehow "used up" in the oil. I was pointing out that the element boron (as measured by ICP or AA) is always going to be the same regardless of whether the parent boron compound is still effective or not - unless that specific boron compound is somehow independently escaping from the bulk of the oil. Any measured discrepancy is due to measurement error or limitation, not the transmutation of the boron into some other element.
 
Originally Posted By: kschachn
This also shows why it is misguided to think that an oil mixture can be evaluated via VOA. Take zinc for example, the VOA only shows the concentration of the zinc atom and doesn't tell you anything about the structure of the coordination compounds. Zinc dialkyldithiophosphates are a variety of compounds and unless you know which exact one (or ones) are being used how do you know that the resulting mixture is overall beneficial to the performance of the oil? You don't.

ICP or AA is like trying to evaluate words and letters on shredded documents. Sure you can tell whether the ink was black or blue or red, but trying to divine words and phrases is not possible. On the flip side there are only so many compounds added to oil containing zinc so perhaps you can take an educated guess, but it should be realized that you aren't measuring the zinc compounds via an elemental analysis at all. You really do not know anything about that via a standard UOA or VOA, only that there is zinc present. I could make up an oil sample using an oil soluble zinc compound that would exactly mirror the zinc concentration of some other oil but would be completely ineffective as a motor oil additive.
Technically, you are correct. However, the oil manufacturers list zinc in the same way on thier PI sheets. Now admittedly this is probably partially for marketing , but I think in general, you can compare zinc levels on PI's or UOA's, in that a reputable manufacturer is probably not going to use a zinc compound that shows up in high PPM's in a UOA or PI, but is ineffective. As an alternate view, let's say when it comes to calcium, I don't care what compound it is, as it appears in LSPI testing, any calcium compound sucks [censored](that's engineering terminology
smile.gif
) . There are lots of "ingredients" that don't show up in testing that the layman sees. In some way, you just have to trust the manufacturer, to an extent. Please don't take this as me saying you are wrong, as you are not.
 
Last edited:
Actually one other way you might see a decrease in some element over an OCI is by the addition of make-up oil which has relatively less of that element. If you start off with some oil that has 800ppm of boron and over the course of the OCI you add make-up oil which has less or no boron, then the end UOA will show less than you started with. It didn't go anywhere or get used up, you just diluted it.
 
Originally Posted By: kschachn
This also shows why it is misguided to think that an oil mixture can be evaluated via VOA. Take zinc for example, the VOA only shows the concentration of the zinc atom and doesn't tell you anything about the structure of the coordination compounds. Zinc dialkyldithiophosphates are a variety of compounds and unless you know which exact one (or ones) are being used how do you know that the resulting mixture is overall beneficial to the performance of the oil? You don't.


Thank you for stating this.

I think a lot of people get confused from UOA's and don't TRULY understand the data.
 
In looking at hundreds of UOA's posted here the past 2 yrs, it seemed to me that the detergents (Phos, Ca, Mg, Na) are often well below the stated specs of the mfg's oil or even the PQIA VOA. I naturally assumed that meant some of these chemicals were being used up over an OCI....sometimes 10-25% lower. If this were just due to lab sampling variabilities, then we'd also see them coming out 10-25% above VOA spec...and we don't. You also see Boron and Moly lower fairly often, yet never the opposite.
 
Originally Posted By: 69GTX
In looking at hundreds of UOA's posted here the past 2 yrs, it seemed to me that the detergents (Phos, Ca, Mg, Na) are often well below the stated specs of the mfg's oil or even the PQIA VOA. I naturally assumed that meant some of these chemicals were being used up over an OCI....sometimes 10-25% lower. If this were just due to lab sampling variabilities, then we'd also see them coming out 10-25% above VOA spec...and we don't. You also see Boron and Moly lower fairly often, yet never the opposite.

Regardless of what you have seen or not seen, elements as expressed via an ICP or AA analysis are not "used up". In order for them to be lower it has to be that the compounds are preferentially volatile compared to the oil or diluted with make-up oil. Assuming neither of these occur then if an oil has Xppm of some element to start with then it will still have Xppm at the end of the OCI. There is no way around it. Atoms are not changing to another element during the OCI.

ICP (and AA for that matter) is not equally sensitive and accurate towards all elements. Some are more problematic than others.
 
Originally Posted By: kschachn
Originally Posted By: SonofJoe
You can get Boron-based anti-wear additives but I doubt if you will find them in many US engine oils.

It's far more likely that the Boron you're seeing on VOAs is from Ashless Dispersant which has been reacted with Boric Acid to improve its seal elastomer compatibility.

I think from the way I read the question, he's saying that a VOA (for example) showed 800ppm of boron but a subsequent UOA only showed 600. He's asking what caused the difference and whether the boron was somehow "used up" in the oil. I was pointing out that the element boron (as measured by ICP or AA) is always going to be the same regardless of whether the parent boron compound is still effective or not - unless that specific boron compound is somehow independently escaping from the bulk of the oil. Any measured discrepancy is due to measurement error or limitation, not the transmutation of the boron into some other element.


That is correct. The boron cannot be converted to another element.

However boron-containing compounds (or boron) can be deposited on engine surfaces. Reducing the apparent concentration in the oil. A lot of these additives are supposed to work by bonding to metal surfaces in the engine.

This is why you see additives "used up", and yes, it doesn't tell you anything about whether they are still working.

The error in measurement will not be 200 ppm. That's huge. AA can go down to ppb.
 
Last edited:
Originally Posted By: camrydriver111
However boron-containing compounds (or boron) can be deposited on engine surfaces. Reducing the apparent concentration in the oil.

That could be, you may know more about that than I do. That process would constitute the element independently escaping from the bulk oil.

However I wouldn't think that could be an indefinite process, once some film is built up I would think that that the deposition process would cease, or some of the already deposited material would eventually strip off the surfaces and re-enter the oil.
 
A VOA of Ultra shows 131 of Boron. My UOA showed Boron as 49. That was my second run of PUP with nothing added. I was wondering why the number changed.
 
From what I'm digesting from comments concerning UOA's is that I shouldn't trust the numbers? And not everything is showing up on an VOA and UOA?

Pennzoil propaganda shows "magic" and "sci fi", but we know it"s science.
 
Originally Posted By: Malo83
Stay away from annual oil changes
cheers3.gif




My last OCI was three years. It took that long for five thousand miles. I was running PUP and Amsoil EAO filter. I have retired since, so I will be driving my Montero more.
 
Status
Not open for further replies.
Back
Top