Trace of fuel in UOA...

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All I am trying to find out is...is a trace of fuel in a UOA more than 0.5%? Or is a trace less than 0.5%. All of my previous UOA read that fuel was <0.5%, but this last one had a trace of fuel.
 
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I wouldn't read to much into it. If you car shows a good history of little to not fuel saturation then it could simple be in the margain of error. You can take 1 sample and send it to 3 different labs and results will always vary. Same case here. If your UOA start showing them as a common problem wpthen I would look into it. As for now all its really doing is giving a very minimum cleaning effect.
 

gregk24

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Originally Posted By: 3800Series
I wouldn't read to much into it. If you car shows a good history of little to not fuel saturation then it could simple be in the margain of error. You can take 1 sample and send it to 3 different labs and results will always vary. Same case here. If your UOA start showing them as a common problem wpthen I would look into it. As for now all its really doing is giving a very minimum cleaning effect.
I am not worried about it, I just wanted to know if a TRACE of fuel was more than the 0.5%, or if it was less.
 

gregk24

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Originally Posted By: Quattro Pete
Why not ask Blackstone what they mean by 'trace'?
I just thought someone on here might know.
 
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Doesnt blackstone usually infer fuel from flashpoint? do they even directly test for fuel%
 
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Originally Posted By: Pajamarama
I have wondered the same thing. Some of my reports have shown "<0.5" and some have shown "TR". Not sure which is more or less.
good question, I wonder how that works.
 
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Originally Posted By: Rand
Doesnt blackstone usually infer fuel from flashpoint? do they even directly test for fuel%
Yeah, they do, and they usually underestimate by a large amount once you get up there in the amount of fuel. I used to have my own method of estimating fuel from flash I would use to 'correct' Blackstones interpretation. But, Ive forgotten it.
 
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I dug up all my old information. Look at the flashpoint in the 'Values should be column' This is their base flashpoint they use to determine fuel %. I don't know what they use to determine flashpoint for a particular oil; it does seem to change but I don't know why. Ive seen 355-400F listed. If the flashpoint of the tested oil matches what they Think it should be above, it will be tagged as trace. For example if it should be >365F and tests as 365F it will be listed as Trace. Every 20F below what they think it should be is 1% fuel. So for the same listing a result of 345F would be listed as 1% fuel. When I estimate from a blackstone report I use typically 400F as my base and use their formula. Most oils have a flashpoint higher than that, however other materials that get into the oil will also depress flash point. For a basic bulk oil I would probably use 385F and for something super high grade maybe 420F. I also evaluate viscosity when I estimate. Ive seen blackstone assign a trace fuel to a synthetic oil that had sheared from a 5W30 to a low 5W20. My fuel estimate was 3-4% which is likely close to reality.
 

gregk24

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I emailed Blackstone and heard back today. This is what they said..."As for a trace of fuel, it's slightly more than 0.5%. A trace is the lowest level we are able to read with our flashpoint method. We can't accurately detect any fuel below 0.5%, which is why when no significant fuel is present we report it as <0.5%"
 
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Originally Posted By: Rand
Doesnt blackstone usually infer fuel from flashpoint? do they even directly test for fuel%
That's right. Totally forgot about the fact that they don't actually test for fuel.
 
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