Engine/Transmission (1994 - 1998) Oil Analysis - High Chromium??

[amsoilman]

fishjack1,

I guess if you stick to the same lab and follow any trends on your particular engine you should be safe.

This is the BEST way!



Wayne

amsoilman

 

[amsoilman]

but on identical samples, about what percentage of difference would YOU suggest is "normal" or "acceptable" variance from one lab to another?

Gary,

I would'nt even venture a guess! In the case of "SOOT" found in used oil, some labs will use "INFRARED" ABSORPTION" to do the test, and will report it as a "numeric" value. Other labs will report "SOOT" as "TOTAL SOLIDS" and is a measure of the amount of fuel "SOOT", sludge, varnish, spent additives, and other Insoluble Contaminants , and is usually determined through Centrifuging a lubricant/solvent mixture, and the results are normally reported in percent volume.



Wayne

amsoilman

 

[Gary - K7GLD]

I would'nt even venture a guess!



Wise of you to not go out on a limb!



But for MY money, alarms and buzzers start activating when I start seeing 100% and greater variations - sure, analysis MIGHT be best used purely as a tracking tool - but to have ANY sort of reliable value, needs to at least fall into the same general values from one lab to another!



What good does it do when customer "A" is showing 100 ppm of iron from his lab, and customer "B" with an identical truck shows 10 ppm?



Do BOTH customers simply write it off as a "lab variation" - or should one of them start being concerned? SMALL variations from one lab to another might be normal and acceptable to some - but RADICAL differences raise issues of reliability and credibility in my mind...

 

[PAbernathy]

Concerned about Oil Testing Consistency

Do BOTH customers simply write it off as a "lab variation" - or should one of them start being concerned? SMALL variations from one lab to another might be normal and acceptable to some - but RADICAL differences raise issues of reliability and credibility in my mind...

I agree. I feel that scientific acceptance of theories and ideas is based on repeatability and predictability. I understand and agree that categorization differences (what goes into which line) potentially affects everybody (like in accounting where Enron hid some expenses... :-laf ), but repeatability is a cornerstone of acceptance for the scientific world.



However, that being said, the main indicator that I will be looking for is trends over time that would indicate changes in condition. But, I need to believe and utilize the numbers when I get a report that indicates a sudden change (such as high antifreeze, or fuel dilution). And I am not getting a warm and fuzzy feeling when I hear that different labs may be expected to get different results from the same oil.



Phil

 

[amsoilman]

Phil,

However, that being said, the main indicator that I will be looking for is trends over time that would indicate changes in condition. But, I need to believe and utilize the numbers when I get a report that indicates a sudden change (such as high antifreeze, or fuel dilution). And I am not getting a warm and fuzzy feeling when I hear that different labs may be expected to get different results from the same oil. [end QUOTE]

Any reputable oil analysis lab will tell you to "trend" your results... ... ... ... . and use the same lab! Don't jump around with different labs, just pick one and stay with it!



Wayne

amsoilman