UOAs of same car, but with thick and thin (xw-20)

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Does anyone here have UOAs that show multiple reports--at least one from a thicker oil, and at least one from a thinner (0w20 or 5w20) oil? I'd love to compare how both oils did in the same engine.

Yes, there are plenty of stellar reports from cars that run thick or thin, but just doing one type doesn't indicate what the results would have been had another type of oil.

So are there any UOAs that show (most likely) a 5w30, and one of the 20 weight oils? I have done plenty of clicking through these forum pages, but there aren't too many, and it is very time consuming to go through each one.
 
I'm looking to compare engine wear, through seeing how high the wear metals are. I realize that folks who test oil and additive packages will measure the dimensions of wear scars, but I can't seem to find any of that equipment in my garage
eek.gif
so I was thinking a UOA would have to do.
 
Last edited:
Originally Posted By: paulri
I'm looking to compare engine wear, through seeing how high the wear metals are. I realize that folks who test oil and additive packages will measure the dimensions of wear scars, but I can't seem to find any of that equipment in my garage
eek.gif
so I was thinking a UOA would have to do.


Actually in the tests I have read about, they pull out the cam and crank weigh them to detect wear.

I think you will not learn much as your test will not be very scientific.
 
Originally Posted By: paulri
Why not?

There are a lot of reasons. For one, the statistical sample size is way too small. Secondly, metal numbers don't correspond to wear. And, there is a lot more. Read Doug Hillary's article here for more insight.
 
Originally Posted By: paulri
Does anyone here have UOAs that show multiple reports--at least one from a thicker oil, and at least one from a thinner (0w20 or 5w20) oil? I'd love to compare how both oils did in the same engine.

Yes, there are plenty of stellar reports from cars that run thick or thin, but just doing one type doesn't indicate what the results would have been had another type of oil.

So are there any UOAs that show (most likely) a 5w30, and one of the 20 weight oils? I have done plenty of clicking through these forum pages, but there aren't too many, and it is very time consuming to go through each one.


In order to get the results you want conditions would have to be EXACTLY the same to base an accurate comparison. Then repeat it several times. Good luck finding two vehicles, or any vehicles driven under the exact same conditions for your comparison. If you want to gauge engine wear you'd have to do engine tear downs, UOA's aren't going to shed much light for you in that department.
 
There is someone else on here who needs to understand this concept of UOAs not being an indicator of wear as well.
 
From Doug's article:

Quote:
it is easy to assume that by carrying out a UOA you will be able to determine how quickly the engine is wearing out. As well, if you change lubricant Brands you will be able to compare the wear metal uptake results and then make a balanced best lubricant choice to make your engine last longer.
Sadly that logic is seriously flawed....

During the last 50 or so years I have carried out hundreds of UOAs on all sorts of engine configurations – and on transmissions, gearboxes and differentials. These were done in consort with four Major Oil Companies (Shell, Exxon-Mobil, Castrol, Chevron-Caltex), my Employers, my Customers and on my own Fleet and other vehicles. Not once were they ever used to discriminate one lubricant from another on the grounds of wear metal uptake!
 
What I had originally in mind was one car that had (presumably) the same driving conditions, showing results for both types of oil.

Originally Posted By: demarpaint

In order to get the results you want conditions would have to be EXACTLY the same to base an accurate comparison. Then repeat it several times. Good luck finding two vehicles, or any vehicles driven under the exact same conditions for your comparison. If you want to gauge engine wear you'd have to do engine tear downs, UOA's aren't going to shed much light for you in that department.
 
OP, one thing to remember when it comes to UOAs is that the range in particle size that they test is quite narrow.
 
There was a recent thread entitled portentously, or maybe pretentiously, "Final Verdict: Thick or Thin".
This was a thread that ran to epic length that brought in posts from just about everybody here who posts much at all including a bunch of folks who know a whole lot more than I ever will. I'm surprised you missed it.
In this thread, the OP did one shortish run of M1 0-40 and another similar run on TGMO 0W-20.
The vehicle involved was an elderly very high miles Toyota with what sounded from the OP's description like a head gasket leak.
The OP UOAed the runs of each oil and decided that based upon the UOA results, a final conclusion had been handed down that wear was lower with a lower viscosity oil.
It need not be said that many here, including me jumped all over his faulty reasoning and the meaninglessness of the results he saw, but the OP would not be swayed.
In short, one run of any oil tells you exactly nothing.
A solid year with multiple UOAs on oil A followed by the same with oil B might indicate some difference of significance, and I am of the school of thought that the wear metals found in UOAs are a good surrogate for actual wear.
Problem is that with a healthy engine driven under typical conditions, you won't see any statistically significant difference in wear metals as measured in a UOA with any two oils of any viscosities. In fact you won't see much in the way of wear metals at all, so there isn't much basis for drawing any conclusions.
 
You do ask good questions on here paulri. I enjoy the fact that you are willing to ask a number of questions. So, that is a very good thing.
 
Originally Posted By: paulri
What I had originally in mind was one car that had (presumably) the same driving conditions, showing results for both types of oil.

Originally Posted By: demarpaint

In order to get the results you want conditions would have to be EXACTLY the same to base an accurate comparison. Then repeat it several times. Good luck finding two vehicles, or any vehicles driven under the exact same conditions for your comparison. If you want to gauge engine wear you'd have to do engine tear downs, UOA's aren't going to shed much light for you in that department.



You will never be able to duplicate the conditions. Even if you could the UOA wouldn't be very accurate in estimating wear, or wear reduction for that matter. Just leaving a few extra ounces of oil in the sump from one change to the next can skew results, along with a host of other things. Wear is determined by tearing down an engine, not a UOA. I laugh when people see iron at 10 ppm, and iron at 15 ppm and automatically [censored]ume that the 15 ppm iron wear is worse than the the 10 ppm. It might be, and it might not be. My point being: Lets say we have a 6 quart sump, this UOA I drain 5.7 quarts of oil, the next change I drain 5.4 quarts and there's an extra .3 quarts of dirty oil remaining to mix with the fresh clean oil. That alone can change everything.

Lets make it easier to understand. Do you think you can duplicate the exact driving conditions, ambient temperature, engine run time, engine idle time, rpms, and speed exactly the same for two OCIs? I say no way. Bottom line a UOA is a tool with good uses, but limited uses.
 
Thanks. I come here to learn. Usually, like this thread, what I learn is not nearly what I expected the answer to be, but that's ok....that's all part of the process. The info to trolling ratio is very high here at BITOG, at least I've found it to be so. Makes it easy for me to ask whatever pops into my noggin.


Originally Posted By: bbhero
You do ask good questions on here paulri. I enjoy the fact that you are willing to ask a number of questions. So, that is a very good thing.
 
Vehicle: 2009 Scion xB
11/23/16 UOA is Castrol Magnatec 0w20 at 80k miles (not 8k)
2/13/17 UOA is Carquest Euro 5w40
5/25/17 UOA is Pennzoil SRT 0w40 with Restore additive, Lead & copper are elevated as they are part of Restore's cocktail mix.
From my experience 0w20 gave me the least amount of wear.



I do not understand why so many people here act like scientists. This is not a test lab, but real world results. Yes they are not 100% accurate, but they still are 80%-90% accurate!!! You cannot simply ignore that!!!
 
Originally Posted By: paulri
Thanks. I come here to learn. Usually, like this thread, what I learn is not nearly what I expected the answer to be, but that's ok....that's all part of the process. The info to trolling ratio is very high here at BITOG, at least I've found it to be so. Makes it easy for me to ask whatever pops into my noggin.


Here's something that I wrote a while back that explains the limitations of the instrumentation used for UOAs when trying to relate wear metals to actual wear:

UOA by ICP is not a proxy for wear. The limits of the instrumentation prevent it from being used as such. It is possible to have "high" wear metals and lower wear than an engine with "low" wear metals. What supporting proof do you have for each data point that is is a valid indicator of wear? An example would be ferrographic particle counts, or measurements of each engine correlating actual wear with the UOA data.

Now, let's talk about the size of those particles that make it into the plasma. You've probably read many times that ICP can see wear particles at about 5 microns. The labs will tell you this also. They are wrong.

The particle size is based on the aerodynamic diameter, not the actual diameter. An ICP is designed to have a hard cut off of 4.5-5.0 microns due to the fact that droplets larger than that destabilize the plasma. That's where the 5 micron figure comes from. The problem is that is the aerodynamic diameter and is based on a spherical droplet of water. Aerodynamic diameter is affected by density and shape. Metals have a higher density than water, therefore smaller particles are required to achieve the same aerodynamic diameter and be allowed to pass through to the plasma.

This is one of the many reasons why "wear metals" do not serve as a good indicator of wear. The ICP only sees a portion of "normal" wear and miss most if not all of the larger particles generated by abnormal and break-in wear. The other is that due to the different densities of the metals the instrument does not see them equally. Given an equal amount and distribution of particle sizes, the ICP could read 4X as much aluminum as lead due to the density difference between the two. An accurate measure of what is in the oil can only be made if the oil undergoes a digestion to put the metals in solution.

The first 5 pages of this presentation cover what I have talked about. The illustration at the top of page 5 shows the relationship visually. They use a material with a density of 4000 kg/m3 for illustration. Aluminum, depending on alloy has a density of about 2700-2800, copper 8940, iron/steel 7850, and lead 11340. Visualize the 4000 kg/m3 circles at half that size and that is roughly the relative size of an iron particle that an ICP can see vs the 4.5 micron water droplet.

Aerodynamic Diameter

Ed
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