Oxidation and Soot

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Have begun researching how I should interpret oxidation and soot levels in a UOA. Haven't had it done yet but I will next fall after extending my OCI out to 2 years on some of my diesel equipment. I think those will be very useful stats in this case, alonside the regular stuff, in determining if I am pushing the envelope too far. Don't think so, obviously, but there are lots of variables and I wanna know for sure.

Not sure yet what I "know" on this topic so I'd just like to open it up to anyone with helpful comments, information or good study resources. I'm most interested in safe vs unsafe levels in both those areas. Also interested in the tests themselves and if accuracy can be a big issue for an "average" lab.
 
Soot conglamerates into globs of gook that act like sandpaper if left unchecked. A good bypass filter and proper oil that keep soot suspended and forming the globs is a first issue that needs to be tackled.

Oxidation and Nitration along with TBN are numbers to watch as the useful life of the oil deteriates. Oils will thicken and Oxidation and Nitration show higher numbers. There are a few that have lots of experience with limits and criteria in the real world......looking forward to them chimming in!
 
Hi,
Jim - Try and find out the engine manufacturer's limits they do vary - they are an importnt starting point

Some engine families have soot limits of 1.5% and others up to 5%(E1131) when using Approved lubricants

In my case about 20 years ago, I lived with 2.5% as the soot condemnation level. This changed for me with newer lubricants being more tolerant of slightly higher limits around 3%

When I changed to a fully synthetic HDEO the lubricant and additive package supplier had some great tales to tell on the subject. The is no doubt that some lubricants handle soot (in a "dissolved/isolated" stste) state much better than others. I had first found this out in a more practical fashion of Brand comparisons in the 1960s

Using a centrifuge I was confident going to 3.5-4% and even 6% at a pinch - the engine maker's limit was/is 3%. IMHE it is the way in which the lubricant handles soot contamination over time that is the real leader here!

I am a great believer in using the TBN - TAN relationship for monitoring the lubricant's condition, along with viscosity take at both 40C and 100C
 
I'd agree with Doug, find the manufacturer's limits as a starting point. Each engine is a bit different so you can't really pick a number and run with it. Taking soot for example, on a Series 50 Detroit I'd be happy to see soot at any level less than 5%. On a Cummins M-11 1-3% are the numbers I'm generally looking for. Each engine and application will be a bit different.

Using the TBN and TAN as general indicators of general oil condition and monitoring soot levels are the foundation of a good diesel PM program. However the numbers are useless without some construct to put them into. If you can't get OEM figures see if you can find some examples from similar equipment and oil if possible.
 
So I guess I need to look for this sort of info on the following engines:

Neuss (IH) D358 6-cyl NA DI (Farmall 826D)
Ford 152ci 3-cyl NA DI (Ford 2810)
Ford (IH) 6.9L V8 IDI (Banks Turbo kit added) ('86 F-250HD)......

Just in case any of you have seen such stats :) < )!
 
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