The reliability of UOA's and what they mean to you

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wemay

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If we can sit in our homes and read, analyze and disect a fellow BITOGER'S oil analysis; recommending in many instances that the mfrs recommendation is not the best for the vehicle, why isnt this true for said mfrs? Theoretically, shouldn't they be able to do the same and get the recommendation right prior to releasing the engine to mkt? Assuming of course that the $20 UOA is trusted over years of engineering prowess... and many do.

What SHOULD be taken from a UOA?
 
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I think you are equating familiarity with expertise.

I can sit home and interpret people's blood tests too.

It is amazing, however, how some engineering decisions apparently were never tested and have been quickly proven poor.
 
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Originally Posted By: wemay
What SHOULD be taken from a UOA?

Excessive fuel dilution, coolant contamination. In addition, TBN/TAN relationship to guide you in safe OCI duration.

Sometimes, very high metal readings can also be used to determine a problem, but these are fairly rare.


Quote:
Theoretically, shouldn't they be able to do the same and get the recommendation right prior to releasing the engine to mkt?

There are way too many variables that they wouldn't be able to account for, mainly the operating conditions. Then there are lab errors to deal with.
 
Originally Posted By: Quattro Pete

Quote:
Theoretically, shouldn't they be able to do the same and get the recommendation right prior to releasing the engine to mkt?

There are way too many variables that they wouldn't be able to account for, mainly the operating conditions. Then there are lab errors to deal with.



Good point...
 
There is an awful lot of second guessing done here without first hand knowledge of all the conditions. People post reports, comments about their vehicle use. But how much idling? How much warm-up? ambient temps? normal trip length?

I did not say average per trip. I drive to or from work 12 times a week. 1.2 miles each way. But every couple of months I drive 450 miles on a trip. Average is skewed.

UOA is very valuable for companies with fleets of a dozen or more vehicles doing the same things.

And some of the analysis reports have comments based on averages rather than proactive suggestions.

After studying about 5000 of them for maintenance suggestions, I can say that most OEM recommendations are right on. Biggest gap left is so many that still don't know the difference between GL-4 and GL-5, and there is a lot more copper in any GL-5 in a transmission than a GL-4.
 
Hopefully one is using a spec'ed oil to begin with. There is the UOA and interpreting the UOA and trending, etc.

However for any one engine's UOA I am not sure its all the valuable a tool to predict how the same oil might perform in a similar engine.
 
Not to be a stickler, but 'reliability' means the same results coming from similar samples. if you split a sample and send one to Blackstone and another to another company, you get the same results. I'd say reliability is excellent

As far as validity goes, That's the question of whether the tests show anything useful. I don't know. All the UOAs I see seem to show that the name brand oil does an excellent job of lubrication if not pushed too far. I've learned a few things from looking at the tests.

1. Quality oils of any brand with reasonable change intervals do well.

2. Its very difficult to discern any measurable improvement with synthetic oils and regular just by reading the UOA.

3. Fiddling with the viscosity within reason doesn't seem to make much difference.

So, I've kind of lost interest in the subject. I've turned my attention to other maintenance issues and resolved to be punctual about oil changes with quality oil and careful about monitoring oil consumption, but not to obsess over it. Last week I had my oil changed at about the 6K mark after 9 months. I would have waited longer, but its going to be difficult to get around to it in time otherwise. I had the differential oil changed instead. That's probably overkill too, but I don't know that its overkill the way it is with oil. I'll probably order up another UOA at about 70K miles to see how things are going, but that's about it.

I don't subscribe to the belief that you are likely to spot an impending engine failure with a UOA that you wouldn't better detect through other means.
 
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Originally Posted By: Quattro Pete
Originally Posted By: wemay
What SHOULD be taken from a UOA?

Excessive fuel dilution, coolant contamination. In addition, TBN/TAN relationship to guide you in safe OCI duration.

Sometimes, very high metal readings can also be used to determine a problem, but these are fairly rare.


Quote:
Theoretically, shouldn't they be able to do the same and get the recommendation right prior to releasing the engine to mkt?

There are way too many variables that they wouldn't be able to account for, mainly the operating conditions. Then there are lab errors to deal with.



I would add looking for silicon intrusion along with fuel and coolant.
 
You're comparing apples and oranges.
The recommendations that come in the OM of any car are usually based upon reasonable maintenance costs versus what's required for the engine to reach the industry standard life of 150K without being worn out.
If you could actually ask an engineer who actually worked on the development of an engine what he uses in his own engine and how often he changes it, you might get an answer somewhat different from what you'll find in the OM.
UOAs are emprical, not theoretical.
If a UOA shows wear metals reasonably in line with those found in UOAs of similar engines, then the UOA indicates that you probably have a healthy engine.
If you see things like high sodium in a UOA from an engine in which oils containing sodium as a part of the add pack haven't been used, then you know to look for a coolant leak.
If you see strong TBN and low oxidation on any given interval in a UOA of oil from your engine as you use it, then you know that you can reasonably extend drain intervals.
If you see a lot of fuel dilution along with the attendant loss in viscosity, you might want to stay with the drain intervals you've been using.
UOAs are probably not all that useful in determing which oil offers the lowest wear, although many of us obsess about a few PPM here and there.
 
Here is something I don't understand...

Take for example, a UOA at 7500 miles with 1 quart added as a top-off.

If this quart was added at 3000 miles the results will look very different from a quart added at 7499 miles... correct ?

From what I understand, a UOA report doesn't account for this. Doesn't this render the UOA basically useless if you add oil?
 
Originally Posted By: fdcg27
You're comparing apples and oranges.
The recommendations that come in the OM of any car are usually based upon reasonable maintenance costs versus what's required for the engine to reach the industry standard life of 150K without being worn out.
If you could actually ask an engineer who actually worked on the development of an engine what he uses in his own engine and how often he changes it, you might get an answer somewhat different from what you'll find in the OM.
UOAs are emprical, not theoretical.
If a UOA shows wear metals reasonably in line with those found in UOAs of similar engines, then the UOA indicates that you probably have a healthy engine.
If you see things like high sodium in a UOA from an engine in which oils containing sodium as a part of the add pack haven't been used, then you know to look for a coolant leak.
If you see strong TBN and low oxidation on any given interval in a UOA of oil from your engine as you use it, then you know that you can reasonably extend drain intervals.
If you see a lot of fuel dilution along with the attendant loss in viscosity, you might want to stay with the drain intervals you've been using.
UOAs are probably not all that useful in determing which oil offers the lowest wear, although many of us obsess about a few PPM here and there.


I will definitely look at UOA's in a different light going forward.
 
Originally Posted By: CELICA_XX
Here is something I don't understand...

Take for example, a UOA at 7500 miles with 1 quart added as a top-off.

If this quart was added at 3000 miles the results will look very different from a quart added at 7499 miles... correct ?

From what I understand, a UOA report doesn't account for this. Doesn't this render the UOA basically useless if you add oil?



No,not useless. You have to take that sort of thing into consideration yourself as you analyze the report. If you plan ahead you can avoid adding the oil if you're that close to draining or sampling. If you're that close to sampling, just maintain oil at the add mark. No need to add a full quart if you're nearing a drain.
 
Originally Posted By: dustyroads
Originally Posted By: CELICA_XX
Here is something I don't understand...

Take for example, a UOA at 7500 miles with 1 quart added as a top-off.

If this quart was added at 3000 miles the results will look very different from a quart added at 7499 miles... correct ?

From what I understand, a UOA report doesn't account for this. Doesn't this render the UOA basically useless if you add oil?


No,not useless. You have to take that sort of thing into consideration yourself as you analyze the report. If you plan ahead you can avoid adding the oil if you're that close to draining or sampling. If you're that close to sampling, just maintain oil at the add mark. No need to add a full quart if you're nearing a drain.


Yes, but I am talking about all these UOA's posted online. We have no idea when the fresh oil was added.

Oil added towards the end of the cycle will skew the results and make the oil in the sump appear more "youthful" than it really is.

I feel like this just adds to the billion variables that can effect an oil sampling report.
 
Originally Posted By: widman
One point I always make.

Oil analysis is a science.
Interpreting the report is an art


And a single snapshot is usually worthless.
 
Originally Posted By: MolaKule
And a single snapshot is usually worthless.

Agreed. It's mainly about trending, looking for anomalies.

Although, a single UOA with very high fuel or glycol content can provide immediate value.
 
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