Why iron ppm numbers are NOT good wear indicators.

[d00df00d]

http://www.lubrigard.com/products/literature/WC-PQ-ANALYSIS.pdf

This is an article from WearCheck about PQ index. I'm posting it here because it shows how the wear numbers on most UOAs can't be trusted.

The article shows two examples of UOA results: one with 286 ppm of iron, and one with 12 ppm. If you ask anyone on this forum, 12 ppm is totally fine and 286 ppm indicates a serious problem developing.

However, once the PQ index is factored in, you can see the reality is exactly the other way around. The 286 ppm example turns out to have no abnormal wear whatsoever, whereas the 12 ppm example looks catastrophic.

How could this be?

Most UOAs are done with a method that counts the number of iron particles that are in a certain range of sizes. If you have particles that are bigger or smaller, the lab can't detect them. PQ index, on the other hand, measures the mass of iron in the oil. No matter how big the particles are, they will be counted.

In the article, the 286 ppm of iron turned out to be made up of of extremely small particles, indicating light corrosion. This means the oil is overdue for a change, but it doesn't mean the engine is wearing out. By contrast, the 12 ppm of iron turned out to be hiding a very serious problem: the engine was wearing badly, but it was chucking out particles that were too big for the standard UOA to detect; hence, the iron number was low even though the wear was catastrophic.


FWIW.

 

[Quattro Pete]

Yup. Same reason why I mentioned in another thread that a magnet is not going to affect a standard UOA reading - metal chunks captured by the magnet are too big to be detected anyway.

 

[ARCOgraphite]

Thats whay I've been repeatably mentioning to look at the filter contents - but do we have a lab that can analyse filter contents for a reasonable cost? You can do it, but you have to be fastideous and it involve solvent washdowns and microscopes ... just a P.I.T

 

[CarbonSteel]

I am new to the UOA game, but it does make me wonder if the Blackstone reports are actually worth it. I can see that most of the UOA is good information (such as fuel/water/silicon contamination), but as you have demonstrated a UOA may not tell the whole story when it comes to wear.

Monitoring wear is my primary goal as I am not interested in extended OCIs, which (at least to me) would not seem to be conducive to minimizing wear (but instead to minimizing cost of an OC).

Does WearCheck offer services to individuals or is there another lab that has a more comprehensive examination?

 

[hate2work]

Originally Posted By: ARCOgraphite
You can do it, but you have to be fastideous and it involve solvent washdowns and microscopes ... just a P.I.T

A pain in the dead horse? I agree

It doesn't take much reading here to figure out that UOAs are not that useful, except for trending. And I'm not even sure that's very useful.

 

[shrooms]

Must have been using Mobil1.

 

[Doug Hillary]

Hi,
d00df00d - I wrote this a week or so ago to Post in another Thread about Fe readings - perhaps it makes sense and is relevant in here

STARTS
Hi,
the levels of Wear Metals (WMs) that show up in "simple" and/or single pass UOAs can be easily misinterpreted. Often the comments from Blackstone's Labs doesn't help and in fact may be misleading, conjecture - or something else, and even amusing at times

It is often forgotten by the "amateur" UOA reader that the actual numbers are in parts per million (ppm) and typically in the change over those shown in a Trended range they are probably meaningless

Firstly each engine has its own "signature" and Trending will establish this over time

Secondly measuring engine lifespan by small UOA movements in Fe (Iron in various formations) for instance is really impossible

Items approx 8microns and up to around 40microns may be circulating in the lubricant and will not be picked up by a UOA. Many will not be removed by a typical FF filter either!

Fe numbers which typically have an "actionable" maximum in UOAs of around 100-150ppm (depending on the engine Manufacturer) can be alarming for some when the movements go from say 10 to 25 over a couple of OCIs! This is typically an over-reaction!

With Fe the true picture is only partially painted by a simple UOA. The rest of the picture is completed by other test protocols. One of these is the PQ Index test. The PQ Index is an arbitrary unit of measurement - individual but linear in Trending. Establishing a Trend ratio between the Fe numbers in the UOA and the PQ Index number is a good place to start!

It can be said that if the PQ Index is lower than the UOA Fe number it is unlikely that large items are in circulation. If the PQ Index rises and the UOA Fe numbers remain the same or fall it is likely that larger items are being circulated. This may be a reason for further investigation

Partical counts to established formats and other tests can then also be used if the UOA and PQ Index indicate a need for more information

So I suggest to all BITOG readers to be very careful when "measuring" engine longevity by simply studying WM numbers - and especially Fe! These numbers are simply a starting point and not the whole story!!!
ENDS

 

[d00df00d]

Germaine indeed, Doug. Thanks!

 

[tig1]

I have noticed for some time now UOAs might detect a coolant leak(I can tell that by a low overflow tank), but are not much value beyond that for me. It amazes me people decide the oil they use solely on UOAs.

 

[porkchop01]

Originally Posted By: tig1
I have noticed for some time now UOAs might detect a coolant leak(I can tell that by a low overflow tank), but are not much value beyond that for me. It amazes me people decide the oil they use solely on UOAs.
I was once one of those people, but have read all your post on this subject and M1. I will be changing my two chevy's over to reg M1 next oci mainly because of them getting the dexos1 lic so soon and it is factory fill in many GM cars. I will not be doing any UOA's on them, just use the OLM and sleep good at night.

 

[Jim Allen]

Again, Doug, a cogent summation of the facts. You see people here engaging in severe hand wringing if the iron levels go up to 23 from 12 ppm and relying on one UOA to be some magic insight into engine condition. To me, it's a great way to check oil condition in determining a OCI (assuming you get a TBN or TAN test done too). As many have said before, the odds of a UOA catching some upcoming failure are pretty slim, especially if no regular, methodical trending analysis has been done.

 

[CarbonSteel]

FWIW; WearCheck offers service to individuals:

2010_FX4,

Yes, WearCheck USA offers oil analysis to individuals.

We have available sample kits of clear sample bottles, sample information form, with a return sample container that we send out to our customers with their request.
Pre-paid Sample kits include analysis when returned to the lab, located in Cary, North Carolina with a turn time of 48 to 72 hours for Reporting Data and Evaluation.
Pre-paid Sample kits have a cost of $24.00 each plus UPS shipping charges.
Credit card information by phone, Company PO # or account billing is required for sample kit orders to ship.

Below is program analysis test description for your review.

Contamination

• (Engine) Coolant / Glycol
• (Engine) Fuel Dilution
• (Engine) Soot Load
• Water
• Silica – Dirt Entry

Wear Generation

• Wear Metals in Parts per Million

Oil Condition

• Viscosity
• Additive Metals for Baseline
• Oxidation (Oil Degradation)
• Total Base Number
• Total Acid Number

Contact us if you have any questions or need for materials for sampling,

Regards,

Tim Vann
WearCheck USA
Senior Sales Representative
Technical Support
Shipping & Receiving Manager
1-800-237-1369
Office 919-379-4102
Direct 919-379-4029
Fax 919-379-4066
Cell 919-524-4608
[email protected]

 

[Spector]

The other thing many labs and people interpreting the results is that iron ppm will increase with miles on the oil but this is normal wear. 20ppm at 3000 miles is a lot different than 20ppm at 10,000 miles but many people only look at the number. I stopped doing UOA a few years ago, I did them on every vehicle consistenly for many years and finally realized they were pretty much worthless for the average driver. I had some really really bad reports but the engines just kept going and nothing ever developed. In most cases, there is nothing you can do to alter a bad result, changing he oil every 2000 miles is not the solution, just gives better UOA results. Very few engines die from catastrophic failure most just wear gradually and after 200000 or 300000 miles the owners decide other parts die but the engines keep going

 

[Quattro Pete]

Originally Posted By: 2010_FX4

Does WearCheck offer services to individuals or is there another lab that has a more comprehensive examination?

I like WearCheck better than Blackstone. Not to mention WearCheck is less expensive. Here is a sample report:

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1437629

You also get a login to a personalized web portal where you can access all your reports and run various reports.

 

[Doug Hillary]

Hi,
please do not let this Thread deteriorate in to the merits on one Lab or another - the OP's title is surely what it is all about

 

[Whimsey]

The wife owned a bought new 2002 Explorer with the infamous 4.0 V-6. it was well maintained by the dealer. Motorcraft 5W-30 & Motorcraft filter every 5,000 miles. This works out to every 4 months, lots of highway driving. Though the last 2 OCI's involved Schaeffer Supreme 5W-30 & around 8,000 miles OCI's.

Started hearing what sounded like a cold temp ping at around 2500 rpm. Had previous OCI's done with Terry. Sent the last sample off to him. Came back that the iron level had shot up tremendously over previous UOA's. Terry thought that it was indicating some major problem. It was! The timing chain tensioners were disintegrating causing the timing chain to flop around and shed metal. The repair cost was in the neighborhood of ~$3000, both front and rear needed to be done.

Traded it for a new 2005 Explorer with the 4.6L V-8. At 90,000 miles it's been a good vehicle so far.

Sometimes the UOA do pay.

Whimsey

 

[demarpaint]

Originally Posted By: tig1
I have noticed for some time now UOAs might detect a coolant leak(I can tell that by a low overflow tank), but are not much value beyond that for me. It amazes me people decide the oil they use solely on UOAs.


+1 Aside from a coolant leak which I can find with my pressure tester I see little to no value in UOA reports. Everytime I get close to seeing value in them something pops up like this thread. Then I realize that in driving and owning cars since the 70's and never doing a UOA why should I start now? I have no intentions of doing extended drains either. I will continue to read them here on Bitog, maybe I'll some day I'll change my mind.

 

[FZ1]

That's right,boys. Net of the variables,Uoas are Alchemy;not Science. Interesting Alchemy,though.

 

[Jim Allen]

Originally Posted By: Whimsey
The wife owned a bought new 2002 Explorer with the infamous 4.0 V-6. it was well maintained by the dealer. Motorcraft 5W-30 & Motorcraft filter every 5,000 miles. This works out to every 4 months, lots of highway driving. Though the last 2 OCI's involved Schaeffer Supreme 5W-30 & around 8,000 miles OCI's.

Started hearing what sounded like a cold temp ping at around 2500 rpm. Had previous OCI's done with Terry. Sent the last sample off to him. Came back that the iron level had shot up tremendously over previous UOA's. Terry thought that it was indicating some major problem. It was! The timing chain tensioners were disintegrating causing the timing chain to flop around and shed metal. The repair cost was in the neighborhood of ~$3000, both front and rear needed to be done.

Traded it for a new 2005 Explorer with the 4.6L V-8. At 90,000 miles it's been a good vehicle so far.

Sometimes the UOA do pay.

Whimsey


As an engine condition monitor, UOAs do work but only when there is a meticulous program. But even when a meticulous program is adhered to, the engine may come to grief and die between the UOAs without being caught by analysis. In your case, you had another symptom that alerted you BEFORE the UOA, noise, so you could have come to the same conclusion without the UOA.

Don't get me wrong, I think you can greatly increase your odds of catching something with regular UOAs but for schlubs like us (well like me... I do not, in fact know you are a schlub ( : < ) it can be a lot of extra money spent with no likely payoff. But, like a slot machine, it does occasionally pay off. House odds, though.

Doing one once in a while is near onto useless. It can be a good snapshot of oil health, and that's how I use it mostly. If you happen to catch something mechanical that way, it's pure luck. Some people like to have fun with it, use it as a learning tool or play "Dueling UOAs" to promote one's favorite brand.

 

[demarpaint]

I agree with Jim, the noise was the tip off. With or without a UOA the repair would have to be made, or in the posters case trade the vehicle in. In that example just based on sound most good mechanics would have been able to make that diagnosis.

Seems to me many times if iron levels are low people think the oil they are using is the greatest. If they are high, then excuses are made that the iron count is meaningless. UOA reports have value to some, I'm still on the fence.