UOA's in single digits, but oil has swirls......

[Fordiesel69]

Help me to understand this:

I drain oil on a lot of our vehicles, and I can see quite a bit of swirl. I can also see very fine metal flake. Yet the UOA's come back very very good. As a matter of fact, everything in the single digits.

So....what is the swirl all about? I know lawn tractor engines shred metal and it is normal to see when there is no oil filter being used. But on cars I am not sure.

 

[OVERKILL]

Originally Posted By: Fordiesel69
Help me to understand this:

I drain oil on a lot of our vehicles, and I can see quite a bit of swirl. I can also see very fine metal flake. Yet the UOA's come back very very good. As a matter of fact, everything in the single digits.

So....what is the swirl all about? I know lawn tractor engines shred metal and it is normal to see when there is no oil filter being used. But on cars I am not sure.


UOA's only pick up VERY small particles. If you have an engine losing metal in visible pieces, that's not picked up by a UOA.

 

[Fordiesel69]

But I see it in almost all different engines, even a 20k mile F-150. Why?

 

[yonyon]

Are you sure what you're seeing is metal and not tiny air bubbles? Tiny bubbles can look shiny. Obviously air in the oil isn't good either but wouldn't show up on you UOA.

 

[Pablo]

$25 UOA's only pick up metals in solution. And maybe SOME very small particles. There are limits to these tools. Just like there are limits to using single measurements about an oil to claim it's "better".

 

[Donald]

If you have an engine loosing metal after break-in you have trouble.

The UOA testing filters the oil of large particles that would mess up the UOA process.

I doubt if you can see or feel the size of the iron particles that a UOA reports.

You can at extra expense get a particle size count as part of a UOA.

 

[OVERKILL]

Originally Posted By: Pablo
$25 UOA's only pick up metals in solution. And maybe SOME very small particles. There are limits to these tools. Just like there are limits to using single measurements about an oil to claim it's "better".


I see what you did there

 

[friendly_jacek]

If you look at used oil at direct sunlight, there are fine particles that are invisible with regular shop lights. That has been my experience at least.

 

[tig1]

A couple of years ago,BuickGN, a poster here had an engine that had a cam,I believe, totally fail but the UOA showed no sign high iron. Outside oil contamination is about the only reason I see to do UOAs.

 

[MinamiKotaro]

I don't think UOAs are good for determining engine wear. They can tell you if the oil has sheared too far out of grade or if the TBN has dropped too low to continue using the oil.

Honestly, unless you do very extended drains, a UOA on a passenger car is mostly for fun, imho.

 

[Brybo86]

Originally Posted By: tig1
A couple of years ago,BuickGN, a poster here had an engine that had a cam,I believe, totally fail but the UOA showed no sign high iron. Outside oil contamination is about the only reason I see to do UOAs.

Did he ever cut open any filters? I would love to see that

 

[OVERKILL]

Originally Posted By: Brybo86
Originally Posted By: tig1
A couple of years ago,BuickGN, a poster here had an engine that had a cam,I believe, totally fail but the UOA showed no sign high iron. Outside oil contamination is about the only reason I see to do UOAs.

Did he ever cut open any filters? I would love to see that


You can probably find his post on it if you search.