Insolubles lead to sludge?

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So if you have an oil UOA, and the TBN/TAN and all the other items checked for in your UOA check out fine, but the insolubles are a bit high say at a 6K mile check, would it lead to engine sludge if you were to run for double or triple that mileage?
 
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I don't know the answer. But to me it seems logical that if insolubles are high then the TBN/TAN would not be ok. But like I said, I have no idea.
 
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StevieC

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I have a UOA where the Insolubles are "elevated" but the TBN is at 6.3 an the TAN is excellent. (can't remember the number but I know it was excellent) So what I guess what I'm asking is what role do insolubles play in your engine... Too much and they become Abrasive? or Sludge Forming? or nothing really at all?
 
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I wouldn't sweat a tick up in insolubles ..but you're projecting out double or triple the mileage frame where the detergent and dispersant properties will not be the same.
 

JHZR2

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That may well be a question to approach Terry on - given the type of optimization that it leads to.
 

StevieC

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He did the analysis and said although it was elevated it wasn't cause for concern yet. But he didn't elaborate on the "yet" part. I just thought I would open it up for discussion here... I have since been able to drop my insolubles by changing air filters and fuel sources, but I was just curious as to what role insolubles play in the engine in terms of wear or sludge buildup etc.
 
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Assuming your filtration is up to snuff, you'll eventually get a bunch of <2um particles. Even with bypass filtration. Not to say that it hasn't occurred, but I've never seen oil in a gasoline engine condemned due to insolubles. Something else trash can's it first. In a diesel, it can be the only thing that condemns it (soot). If your dispersant package isn't up to snuff, it can form deposits. If it is and you leave it in long enough ..it could be abrasive. This is rhetoric that I've either heard or read. I've never personally experienced/observed it.
 
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I was not aware that Dyson Analysis tested for insolubles. This must be a new feature. I'm not quite sure how you could even detect engine deposits on a UOA sample if the deposits are sticking to an internal engine component. If you are trying to avoid engine deposits in earnest, then use a maintenance dose of ARX on every OCI. The difference will be very noticeable on your oil filters after an OCI. This is what I have noyticed on my brand new RAV4 V-6.
 

StevieC

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 Originally Posted By: INDYMAC
I was not aware that Dyson Analysis tested for insolubles. This must be a new feature. ...
It was done at BlackStone and analyzed by him. In future I will be sending my samples to his lab.
 
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Hi, StevieC - Your question can be answered by a "yes". But, as always it is a "qualified" yes! The TAN/TBN relationship is always a balance IMO and I always obtained both in diesel engine UOAs. Many Labs do not get it right so maintaining a trending balance IMO is best (my database showed this to be mine (TAN 6.7 /TBN 2.6) at OC point (condemantion point for TBN 1 (D4739). Note this was NEVER a condemnation point - soot or iron always was!!! It is wise to know what the engine manufacturers's condemnation point for "insolubles" is - typically it will be around 1% (D893). Soot can be up to 5% depending on the quality of the lubricant and the engine's design Some lubricants handle insolubles much better than others IME. "Simple" UOAs are a poor tool to determine if "sludging" is occuring but they may is some cases be an "indicator" especially with extensive trending on one engine or an engine "family" I hope this ramble helps?
 

StevieC

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Doug, Many thanks for the input. I will send you a copy of my next UOA for you to have a look at and comment on as I respect your opinions.
 
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 Originally Posted By: Doug Hillary
It is wise to know what the engine manufacturers's condemnation point for "insolubles" is - typically it will be around 1% (D893). Soot can be up to 5% depending on the quality of the lubricant and the engine's design
Much easier said than done
 
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