The Problem with Using UOA's for Wear is.....

[ZZman]

It is not controlled enough to make valid comparisons.

Unless the same engine is run under the exact same conditions who really cares if one oil has 10 ppm for iron and another oil has a 20 ppm reading?

There could be any number of reasons why the car with the higher reading is higher.

Maybe the car was run in colder weather
Maybe it was started up more times
Maybe it hauled more weight at times
Maybe it was revved higher
Maybe it was idled more often
Maybe more abrasive particles entered the engine
Maybe the filter didn't filter as well
Maybe it got more city use and less Hwy use

I would love to see controlled wear studies.

Just because the vehicle had roughly the same mileage on it for the UOA's doesn't mean it was driven the same or had the same conditions placed on it.

 

[c3po]

Along with a UOA I would also like to see a Particle Count Test.

 

[dsmith41]

I use UOAs to show the condition of the oil and if any antifreeze or insolubles are present. Of course if wear really is bad, like if bearings or pistons are melting, it will show up. But I agree, most people are splitting hairs with wear metals in their UOAs. The important thing is trending data.

 

[Corvette Owner]

BUT, if you use your OLM to determine WHEN to change the oil, that should choose a consistent usage point.

 

[c3po]

Originally Posted By: dsmith41
The important thing is trending data


I definetly agree with dsmith41's comment.

 

[BuickGN]

You guys are all missing one point. The typical $20 UOA only picks up a very narrow particle range. It's been shown that a quickly wearing part normally produces wear particles too large to be seen by the UOA thereby producing a "good" UOA. On the other hand you may get a good oil that reduces wear thereby reducing particle size which would show up as a higher PPM on the UOA. You just can't use them for determining which oil is best based on wear metals.

I've mentioned the two very quickly failing engines I've had with sparkly oil that multiple UOAs did not pick up on. Upon teardowns, the rings were half the weight they were when the went in, cylinders were void of hone marks with a large wear ridge at the top, rod and main bearings were down nearly to the backing plates, and I had one cam lobe starting to go flat.


They're great for many other things and I plan on getting one done soon on the TL to check other things but I won't even look at the wear metals.

It's almost comical that people still base oil preference on a few PPM of wear metals with all of the info out there today.

 

[nfs480]

Originally Posted By: Corvette Owner
BUT, if you use your OLM to determine WHEN to change the oil, that should choose a consistent usage point.


Not quite, there's still far too many variables, like the exact number of miles you drive and conditions after it starts telling you you need to change.

 

[Corvette Owner]

Originally Posted By: nfs480
Originally Posted By: Corvette Owner
BUT, if you use your OLM to determine WHEN to change the oil, that should choose a consistent usage point.


Not quite, there's still far too many variables, like the exact number of miles you drive and conditions after it starts telling you you need to change.


OLMs track total rpms not miles (miles aren't that important, piston travel is) and they take into account oil temperature, modern OLMs are pretty good.

 

[Pablo]

Originally Posted By: c3po
Along with a UOA I would also like to see a Particle Count Test.


Problem is, particle counts are often even more inaccurate than UOA's.

 

[Audi Junkie]

I think a bad UOA is a bad UOA, and a good UOA is a good UOA, it's that simple.

I have a friend who posted a Corvette UOA here that was horrible. He was using the speded factory-fill Mobil 1 5w-30. If that oil was working well, HOW IN THE WORLD WOULD THE UOA BE BAD?

otoh, I have another friend who posted a PP 5w-30 UOA in an Audi turbo that was great. Now, that's not a speced oil for that engine, but it did great. I ask again a similar question, if that oil was bad for that engine, how would the UOA come out "clean".

 

[Ben99GT]

Originally Posted By: Audi Junkie
I think a bad UOA is a bad UOA, and a good UOA is a good UOA, it's that simple.


If you're talking about the condition of the oil, sure. If you're talking about an oil's anti-wear characteristics based on a few ppm of wear metals, it's anything but that simple.

 

[Corvette Owner]

Originally Posted By: Audi Junkie
I think a bad UOA is a bad UOA, and a good UOA is a good UOA, it's that simple.

I have a friend who posted a Corvette UOA here that was horrible. He was using the speded factory-fill Mobil 1 5w-30. If that oil was working well, HOW IN THE WORLD WOULD THE UOA BE BAD?

otoh, I have another friend who posted a PP 5w-30 UOA in an Audi turbo that was great. Now, that's not a speced oil for that engine, but it did great. I ask again a similar question, if that oil was bad for that engine, how would the UOA come out "clean".


Maybe your friend with the Corvette drove the car VERY HARD and your friend with the Audi drove easy ? There are many factors in engine wear.

 

[dnewton3]

This topic seems to come up at least once a year. So, it's about time we cover it again, I suppose.

UOAs are tools, like any other. They have good, proper uses, and they can be mis-used, or even abused.

UOAs are a direct indication of the lubricant's relative health. But they are only an INdirect view of the equipment health.

To know how well (or poorly) an engine is wearing, you have three options.
1) take a swag
2) take UOAs
3) do teardown analysis.

Option 1 isn't very reliable. 'Nuff said.
Option 3 is very telling, but also grossly expensive and time consuming. Most of us would agree there is no real-world value to us "common" folks doing a teardown every year to check the Camry engine ...

That leaves us with option 2. UOAs can be a reasonable view of relative equipment longevity. Again, it's an INdirect view, not a direct view. There are implications that must be assumed.

First, singular UOAs are not worthless, but they are not the "tell all, be all" either. If your wear metals are low in the UOA, and your equipment is of known good mechanical conditions, then one can presume that the fluid is doing a decent job. What you CANNOT determine is how one UOA would suggest better/poorer performance against another fluid option. Not enough data exists from a singular UOA. In other words, one UOA can show that the wear is reaonably low, but you cannot judge one fluid against another.

As mentioned, trending and ranges are needed. Here is where UOAs can shine, and help choose one fluid over another. Unfortunatly, to get a true statistical view, you have to have 30 (thirty!) samples under the same (or as close to "same" as you can get) conditions. Even at 5k mile OCIs, that would be 150k miles of UOAs! That's crazy expensive. So, we make inferences from much smaller samplings. It's no longer mathematically viable, but it's also "palletable" from the fiscal sense. This is why UOAs are often a "toy" we mess with here on BITOG, but not really viable in a pure scientific sense.

UOAs are truly limited in scope; they cannot see above 5um or so. If you have a large "event", it's quite possibe that it will be either missed entirely, or mis-interpreted, because much of the data goes unseen. Not much we can do about that. PCs are good data, but they only tell Size and Quantity, but not composition! Hence, there is no perfect answer (except the tear-down, which we already ruled out due to expense and time).

So, we're left with a tool that is useful, but only if you know its benefits and its limitations. It is not a panacea of knowledge; it's an indicator.

I use UOAs to judge things that are direct, such as TBN. I can get a direct understanding of how long I can leave a fluid in with this data. It's NOT the ONLY thing to take into consideration, but it's one piece of info that has a direct influence on my decision of lubricant longevity. Even if your wear metals were near zero, you'd likely not use a lube if your TBN was too low, regardless of how "good" you thought the wear was.

UOAs, as we know, also help with seeing what kind of mechanical condition you may be running. Fuel, coolant, and dirt contamination can be discovered via UOAs. Further, you can also discover "goof ups". I once helped a guy at another site diagnose the fact that he plumbed his brand new bypass filter in reverse because the UOA had crazy high wear metals. (Basically it caused a dead-head of flow against the FF filter ADBV, and was only passing oil via the really small restriction in the bypass mount. The pressue gage on the dash didn't know any difference, because the pump will still working, but the relief valve was probably full open!) If he'd never got the UOA, and just "presumed" his plumbing work was OK, I doubt that engine would have lasted very long. We don't know how much damage was really done (again, no teardown) but we certainly can assume that the UOA tool helped diagnose a previously unknown problem!

UOAs are not perfect. But they are a tool that can help when used appropriately, and knowing the pros/cons of the approach.

One downside to UOAs is that they can not be cost effective, especially in small sump systems. If you believe your engine is in good mechanical condition, there is little reason to UOA at every OCI; it's just not cost effective. There are times when you can count on the statistical "goodness" of world-at-large to help you avert disaster. The VAST majority of people go about their daily driving lives without synthetic fluids, without bypass filtration, without UOAs and without any mental lubricant stress. And yet, their vehicles keep on truckin', so to speak. You have a very high percentage chance of having no real problems, even without UOAs, because the quality of design and manufacture of today's equipment and lubricants are just so darn good.

In a sense, the expenditure of a UOA is really a choice no different that those of "wanting" to use synthetics for 4k mile OCIs. It's often a waste, but also a mental sense of insurance. Only if you use the tool appropriately can you glean the value from it! As with all things in life, there really is no one, perfect answer for all things.

You can choose to never do a UOA, and just OCI at the OEM rec's. And you'd likely be fine for a very long time. But the UOA gives you a great basis for knowing (or presuming) a multitude of things. UOAs are great tools when "used as directed". Will you know with absolute certainty how the wear is going in your engine? Nope. But you can make some fair conclusions, when certain conditions are assumed.

The UOA does not give you a crystal clear "transparent" view of your engine. Rather, the UOA is better defined as being "translucent". But it sure beats the alternative of being "opaque"!

 

[tig1]

Here is BITOGs "Oil Analysis" report. It shows wear metals in the normal range are much higher than what many here go ape over. I did two UOAs a little over ayear ago and have determined they are awaste of money for me and the average engine most of us have.

Now if I suddenly started loseing water then I would take a sample and send it in, but beyond that I see little value in them.

Here is the link to BITIGs paper on UOAs.

http://www.bobistheoilguy.com/cms/index.php?option=com_content&view=article&id=50&Itemid=56

 

[Spector]

I did the UOA for years, a binder full of results on several vehicles. I concluded the same result as the author, and I had several years of results for trend analysis. Unless a problem suspected, ( coolant in oil etc) UOA are pretty much useless and a waste of money. Nice to play around with and analyze but for something to really use in maintaining your vehicle not cost effective.

 

[AEHaas]

There is value in UOA. The quality of the test is important as is the interpretation. Those counting larger particles, soot, acid and a host of additional tests tell you more about the condition of your engine. You basic, inexpensive, UOA is best to tell you the condition of your oil and to indicate a small number of other issues. Some examples are dirt ingestion, coolant leakage, fuel dilution, and corrosive wear.

The addition of oil filter paper analysis, paper drop tests, visual inspection of engine parts when available add to the overall determination of how well an engine is doing. Basic facts as engine oil temperature, your gas mileage, and engine noises may help in the assessment.

But even the most basic UOA may give you an indication of wear even though the level of “wear metals” may be normal. If the zinc level is dropping fast there is an indication that it is being used to protect metal surfaces from oil starvation. A fast drop in TBN may indicate impending corrosive wear.

The use of radioactive metal tagging and counting shows that the measurement of metal wear particles can be very accurate in the determination of engine wear. One has to be careful to count the radioactivity in the oil and the filter. Catastrophic wear will show radioactivity in the oil filter as well as the oil whereas “normal” wear will only show up in the oil. Radioactive particle counts pick up all sizes of particles whereas the usual, inexpensive UOA only counts the smaller particles.

aehaas

 

[EMPIRE]

here's how i see why one would use UOA.

1. using a new oil, you want to see what usage does to the oil's TBN and viscosity. UOA is a tool to help decide which oil meets your OCI requirements.
2. next is contaminants levels. for the most part, i plot the #'s from each UOA and watch for anomalies (weird dips or spikes). if something shows odd i try to explain it by a change in driving habit or environment, otherwise an anomaly means i need to do further investigating to account for it (it's a possible sign of something to come, etc).
3. UOAI (UOA Interval) i guess can be debated. i did two UOA's on my new car with two different synth oils ran at different OCI's. this got me to the point where i am confident that i am getting every $'s worth out of the oil without compromising function. i am now doing 10k OCI's and i'll do UOA every other OCI.

so, in the end i dont think its really a debate of "is UOA worth it", its a debate of UOAI, which can be different vehicle to vehicle (or even same motor in different cars) due to countless factors that affect UOA results.

i am in the "UOA's are helpful" boat, but use them wisely.

 

[Gary Allan]

Originally Posted By: tig1
Here is BITOGs "Oil Analysis" report. It shows wear metals in the normal range are much higher than what many here go ape over. I did two UOAs a little over ayear ago and have determined they are awaste of money for me and the average engine most of us have.

Now if I suddenly started loseing water then I would take a sample and send it in, but beyond that I see little value in them.

Here is the link to BITIGs paper on UOAs.

http://www.bobistheoilguy.com/cms/index.php?option=com_content&view=article&id=50&Itemid=56


With all due respect to Doug (and I sincerely mean that- I'd give anything to view the world through his eyes and experience) , I often find that what he doesn't say is more important to me than his presentation.

He states that a single "snap shot" is not enough to draw conclusions on. Agreed, as Aristotle said, "One swallow does not the summer make". Both are considered very wise men.

Doug has also offered that if done in conjunction with PQ, ferrography, and whatnot, that they're more accurate.

What he hasn't revealed is how UOA proved out with all the aforementioned confidence bolster tests ...if you just pretended you never did them.

That is, does the UOA track/contour the results shown in these validating (or more confidence supporting) tests?

..or to be more "fuzzy" ...

Does UOA tend to "more" contour to REAL results ..or not?

I've never heard/seen him say that there is NO CORRELATION between a given UOA indication and the rate if wear (trending and whatnot taken as a given).

I think he just wants to give a "quality" presentation ..and lead us not off to the nether world with some false sense of security or hysteria. We're mostly children in comparison and a little (incomplete) knowledge can be a dangerous thing.

That naturally concedes that one will not know the "amount" of wear, but one should be able to glean some "rate" of wear or the change in rate of wear indicators.

There's just nothing to index the rate to the amount in a cheap UOA.

When he says that UOA is unlikely to predict a catastrophic failure, ....sure. Most catastrophic failures are, by implied definition, insidious until they occur. That is, the device/engine/machine was 100% functional before the catastrophic event.

Doug would never recommend, nor I suspect his OEM testing involved, the use of non-spec'd fluids ..other than the success and failure of creating them.

Many of us run out of spec fluids. Many of us run out of spec power outputs. What is one to do without a R&D facility and $$$ to run it?

 

[Steve S]

Are we referring to the 25 to 30 dollar uoa? All the above and it is a possible warnig to potential problems but mainly tells how the oil is holding up.

 

[buster]

Quote:
Unfortunately, oil analysis is not very good at distinguishing wear between different formulations. Emission spectroscopy has a particle size limit of 3 to 5 microns, which means that particles larger will not be detected. Unfortunately, most serious wear issues generate wear particles in the range of 5 - 15 microns. Oil analysis only measures about 15-20% of the particles in the oil, and changing form one formulation to another is likely to change the particle size profile. Usually formulations with more antiwear additive will more aggressively react with the metal surface and when rubbing occurs will produce smaller particles. Generally, more antiwear additives will give greater iron spectrochemical numbers, even though the total iron can be lower. There are other techniques such as ferrography, which looks at the wear particles under a microscope, but now we are talking about analysis many times more expensive than spectrochemical analysis. The oils with the better spectrochemical numbers will be much less chemically active on the metal surface, so they will be less able to handle more severe loads. There is always a trade-off between chemical wear and adhesive wear. Chemical wear is the very small particles and soluble metals which is identified in the spectrochemical analysis, while adhesive wear is many orders of magnitude greater than the chemical wear, but much is not identified in spectrochemical analysis. But if you were using spectrochemical analysis as a maintenance tool and started seeing a deviation over the baseline, then you would know something was wrong.

It is very difficult for an individual to be able to look at numbers which will conclusively determine the best formulation, you simply have to rely on the reputation of the marketer and whether you trust the marketer's technical expertise. There are always trade-offs in engine oils, and we try to enhance antiwear and friction reduction at higher temperatures and loads, while trying to maintain performance at lower and normal loads and temperatures.