Sludge, Varnish, Deposits

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Some uos's show oxidation/nitration. Others show only the level of insolubles. I am not convinced that uoa's can give any real indication of the state of engine cleanliness. I think uoa's are valuable, but I'm skeptical of extended drains. Can't a potential sludge bucket show great numbers?? I think so.
 
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If your seeing high oxidation/low TBN and high insoluables, I'd think that is a recipe for an engine that will get dirty over time. But nothing beats a tear down. Costly though. Using a good synthetic with a good dose of esters helps keep an engine clean.
 

haley10

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quote:
Originally posted by buster: If your seeing high oxidation/low TBN and high insoluables, I'd think that is a recipe for an engine that will get dirty over time. But nothing beats a tear down. Costly though. Using a good synthetic with a good dose of esters helps keep an engine clean.
i agree, but I think you can show good tbn and under the ,6 insolubles and still have a problem. I'm just saying that a uoa only gives you slight insight into this not the whole picture. Your brain and knowledge of oil will be much better than a uoa in determining oci than uos's??
 
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There is Auto-Rx and Lube Control/Fuel Power that has been mention as a safe engine cleaner you might be interested in. From the post by many who claimed great results by these products you may want to look into that direction.
 
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quote:
If your seeing high oxidation/low TBN and high insoluables, I'd think that is a recipe for an engine that will get dirty over time.
I agree, but to haley10's point - I think it's the rate of oxidation and TBN drop that will tell you how dirty an engine is without a true tear down. Any modern oil and for sure synthetics (especially ester bearing oils) will posess the ability to solubulize some portion of the deposits, to the extent it will effect the oil readings (complete cleaning is a different topic). So a fairly rapid change in TBN and insolubles after oil change can signal deposit build up. I don't really think a dirty engine can hide for long if you do semi-regular UOA's.
 
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quote:

I think uoa's are valuable, but I'm skeptical of extended drains
quote:

Depends on your definition on extended drain interval with synthetic oil. I will agree dino or synthetic if the oil is extended there are variables on type of engine driving condtions... every engine has a different make up it can cause the engine to be uncleaned either way. There is no sure thing when using dino or synthetic but common sense as every driver face what he feels is his OCI that will keep his engine in a pratical sense. I don't believe even with synthetic oil during the long run an engine will not get dirty to some degree. It's just the make up of combution, it's not perfect and that is why we tend to be conservative in our OCI. If you feel comfortable with your OCI and feel your engine will run to it's extent in the long run be all means be yourself. There is only one thing I will agree on is: If you do go with extended OCI with synthetic oil the cleaner the engine the synthetic oil has a better ability to perform in it's synthetic state. Synthetic oil needs a clean enviroment to perform to it's ability and any undo residue will easily be washed into the synthetic oil because of it's ability to clean whatever is in the engine. Unlike dino oil...synthetic has a washing effect and is very sensitive in it's ability to extend it's full potential in extended OCI if containminated with washed up residue. A con for synthetic oil if not used properly....
 
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My guess is that an expert like Terry can probably tell something from a UOA. I tend to use the precautionary principle which is to not push it beyond 5 to 6k. Oil is cheap, why push it? The headache of having to worry about whether my oil is "holding up" past 10k is not worth the $30 saved. However, even for short intervals, I don't like my oil changing viscosity as it indicates shearing, etc. That's why I no longer use Valv. Synpower 5w-40 even though I got great wear rates.
 
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