UOAs/VOAs: Are they reliable?

[SwedishRider]

I recently sent in a virgin oil sample to two labs: OAI and BlackStone. The results weren't exactly accurate... in fact, they were very inaccurate across the sample runs. Take a look: https://bobistheoilguy.com/forums/threads/g-oil-ult-biodegradable-full-synthetic-0w-20-voa.206333/

Are used oil analysis/VOAs reliable? Across those 3 sample runs by 2 different companies, the only consistent value was the lack of contaminants from the bottle. But everything else from the viscosity to TBN to add pack values were all different by a WIDE margin, sometimes even within the same company's testing.

Am I right to question the validity of these tests? I'm really starting to think they have little to no usefulness, practically or theoretically.

 

[stranger706]

Originally Posted By: JimCT
Am I right to question the validity of these tests? I'm really starting to think they have little to no usefulness, practically or theoretically.


Well as a whole UOA should be pretty reliable. I'm not sure why there is so much questionable data from Blackstone. At work we use UOA on a regular basis (aviation) and we use that information to decide whether or not to change out a million dollar engine. Lots of industries use UOA in a similar way.

 

[Donald]

I would trust OAI which is Polaris as they are much more geared towards commercial and industrial. With engines costing tens of thousands of dollars to hundreds of thousands of dollars and people are using the UOA to determine when to change the oil. So a lot riding on the UOA to be correct.

Blackstone is geared towards auto enthusiasts. And does not give oxidation or nitration. And more expensive.

 

[FutureDoc]

3 Samples, two companies... and you want reliability?

If you want to determine reliability, you need a much large sample size (across more companies if you want to question the methid) and this is where statistics is key. Need a bigger N to look for reliability.

Still a test is only as good as it tests.

 

[SwedishRider]

Originally Posted By: FutureDoc
3 Samples, two companies... and you want reliability?

If you want to determine reliability, you need a much large sample size (across more companies if you want to question the methid) and this is where statistics is key. Need a bigger N to look for reliability.

Still a test is only as good as it tests.


Statistically, you are correct. My wallet would object to the methodology in that case. I look at it this way... all three of those tests should have come back within a reasonable margin of error. If there are SOP that are followed across the industry with machines calibrated in a standardized way... those results shouldn't have happened.

At least a few folks on this board have come forward indicating they too have gotten ridiculous results from used oil analysis and have since abandoned the practice... so I'm inclined to think this isn't an isolated incident.

 

[Shannow]

Just hope that your pathologists and diagnosticians are doing a better job...