Simple, straight forward question

[DocB]

If a good single bypass filter filters out all the harmful wear metals (in addition to other contminantes) and you sent off your oil for UOA, then how do you know what your wear metals actually are?

 

[Gary Allan]

Good question.

Keep in mind that although UOA can show you problem areas of wear, it's primarily designed to tell you the condition of the oil. Typically, the wear is what the wear is and you're mainly looking for changes or oddities.


This part won't really answer your question, but it may give you additional thought on the matter..

One way that you could determine the effectiveness of bypass filtration in wear reduction would be to run without a bypass for XX miles ..sample ..DIGEST IT (add acid to the sample to reduce all metals to the particle level) ..then add a bypass and run it for a spec'd amount of time (a few hours) ...DIGEST that sample ...then change the oil and run the same (but new) oil for the same mileage with the bypass on for the whole time and see if the two bypass filtered samples are identical. That would determine if the bypass eliminated any "additional wear causing" particles that produced "resultant wear particles".

So far, no one that I know of has done this comparison in that manner.

 

[tigrpal]

A related question - Since TP filters absorb water in the oil so well, won't they also absorb coolant? Therefore a UOA won't be able to tell you if you have coolant leaking into the oil?

 

[unDummy]

The additives and even wear will be present. All filters have limitations.

 

[LargeCarManX2]

Quote:

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The additives and even wear will be present. All filters have limitations.

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To bring this thought process further, if a bypass filter takes out a certain size of wear metal the smaller ones still show in quanity to show excessive lets say lead, copper, etc wear! as unDummy say's all filters have limitations! and thankfully so.

 

[DocB]

Thanks guys, but I still am wondering.
The digest test sounds good, but I don't have the means to perform this operation.
So if I understand so far, a UOA will only tell us the condition of the oil and changes in the wear metals that got through the filter?

 

[unDummy]

Yep, and this is one reason why UOAs need to be tracked and used as a tool.

Drawing conclusions with a 'single' UOA is all but meaningless, unless there is imminent doom pending.

The benefit of the bypass filter is to remove soot, sludge, insolubles.....
There really isn't much wear in an engine without issues.
The soot/insolubles is one issue that can ONLY be addressed with the bypass filter. This issue is now greatly exaggerated due to longer oil change intervals, emissions control, more stress on the engine, and consumers that do not know how to use a dipstick.

We already use a full flow filter. But, we almost NEVER question it in the UOA section. How accurrate is ANY UOA?
Since we don't worry about the full flow, make an effort not to worry about the bypass filter. It's there, it will remove some wear, it should remove all smaller contaminents hopefully reducing abrasive wear,..... and as long at it doesn't become an issue, use it and track UOAs.

 

[DocB]

Thanks. I will.

 

[DocB]

BTW, the last UOA I did I sent out to 2 different Labs.
Same sample exactly. I was very careful.
Came back with 2 very different results.
?????
Can leave one very sceptical.
I called both labs, but it seems no one in this world knows what's going on anymore.
I sure do miss the old days.

 

[Gary Allan]

There was a study of foreign labs (oddly it didn't have any US labs included) that showed that duplication of readings from identical samples was an oddity at best between labs. The results tended to contour each other, IIRC. I'll see if I can find the link that 427Z06 gave me on this topic.