Benefits of Oil Analysis -Machinery Lubrication

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wemay

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Some here have said UOA don't tell you if wear is occurring, only the condition of the oil...

https://www.machinerylubrication.com/Read/29004/oil-analysis-benefits

"The levels of iron and aluminum can warn of piston and cylinder wear before a major failure occurs. Bearing wear rates can be determined and action taken before the crankshaft becomes badly scored. Fuel dilution, anti‑freeze leaks and water entry can be detected while they are still minor problems. The levels of contamination and combustion soot within the oil can indicate a restricted air intake system, ineffective oil filters, poor combustion or a rich air/fuel ratio."
 
I think most would agree that wear happens. I think they would agree analysis can show wear. However most would probably agree that it is hard to determine wear patterns to an exact level to determine what oils may be better or worse. Driving styles, mileage, dirt ingestion, driving style, idle time, cold starts, cold weather starts etc can all affect the numbers.
However a large abnormal reading or a spike can show a potential problem.
 
Originally Posted By: wemay
Some here have said UOA don't tell you if wear is occurring, only the condition of the oil...

https://www.machinerylubrication.com/Read/29004/oil-analysis-benefits

"The levels of iron and aluminum can warn of piston and cylinder wear before a major failure occurs. Bearing wear rates can be determined and action taken before the crankshaft becomes badly scored. Fuel dilution, anti‑freeze leaks and water entry can be detected while they are still minor problems. The levels of contamination and combustion soot within the oil can indicate a restricted air intake system, ineffective oil filters, poor combustion or a rich air/fuel ratio."


I don't think that's accurately representing the consensus here, and certainly not what I've stated on the subject. What you've provided is consistent with what Doug Hillary has posted, which is that UOA's can provide valuable data to identify intake tract leaks, coolant ingress, fuel dilution...etc. When trended, significant departures from the trends in wear; that is, abnormal outliers, can indicate a mechanical problem worth investigation.

Each piece of equipment will have its own "wear rate" and engines within the same family will generally have similar wear rates. When your PPM per 1K miles changes significantly for a given metal, this can be cause for concern.

Some examples:
- GM LS1 trended analysis establishes 5ppm/1K miles (25ppm on a 5,000 mile OCI) as normal for Iron. Next UOA shows 75ppm on the same interval, 3x the wear rate. Would you go looking for something?

- Subaru H6 trended analysis establishes 0.25ppm/1K miles as normal for aluminum. Next UOA shows 10ppm on a 5K interval and 25ppm silicon. Would you go looking for something, and if so, what?

- Ford Modular trended analysis establishes 0.2ppm/1K miles as normal for aluminum. Next UOA shows 20ppm on a 5K interval as well as 10ppm of tin. Everything else seems normal. Would you go looking for something and if so, what?

- GM LT1 trended analysis establishes 0.2ppm/1K miles as normal for lead. Next UOA shows 20ppm on a 5K interval with copper pushing up slightly as well. Would you go looking for something and if so, what?

- Ford 302HO trended analysis establishes 1ppm/1K miles (5ppm on a 5,000 mile OCI) as normal for Iron. Next UOA shows 10ppm in the same interval, you changed oil brands. Would you go looking for something, if so what, and why?
 
Got it.

I don't remember who stated it but it has been said a few times by different members. Maybe a misunderstanding on my part.

Every industry related piece of literature I've read unequivocally states that wear is gleaned from trending UOA. So yeah, surly my misunderstanding.
 
Originally Posted By: wemay
Got it.

I don't remember who stated it but it has been said a few times by different members. Maybe a misunderstanding on my part.

Every industry related piece of literature I've read unequivocally states that wear is gleaned from trending UOA.


Yes, you can glean what "normal" wear, within a range, is for a piece of equipment and then watch for departures from that trend. What you can't do is run Oil A and then Oil B and determine which oil is "better" based on small variances due to the narrow range of particles sampled, chelation and other factors. UOA's simply aren't precise enough for that usage, which is outside their intended purpose anyways, and there are far too many variables in play to allow any sort of reasonable inference based on that approach.
 
Originally Posted By: OVERKILL
Originally Posted By: wemay
Got it.

I don't remember who stated it but it has been said a few times by different members. Maybe a misunderstanding on my part.

Every industry related piece of literature I've read unequivocally states that wear is gleaned from trending UOA.


Yes, you can glean what "normal" wear, within a range, is for a piece of equipment and then watch for departures from that trend. What you can't do is run Oil A and then Oil B and determine which oil is "better" based on small variances due to the narrow range of particles sampled, chelation and other factors. UOA's simply aren't precise enough for that usage, which is outside their intended purpose anyways, and there are far too many variables in play to allow any sort of reasonable inference based on that approach.


Yes, to establish any trend one would need to use the same oil/OCI throughout an established period of time. Jumping from one oil to another may throw things off.
 
you can bet the cheap oil analysis most get DOES NOT compare with oils checked for very $$$$$ machinery that use a LOT of oil for as long as its still good!!
 
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