Fe iron content in UOA's

[Dale_Knight]

As this is more of a general UOA question I'll put it here but if it's in the wrong area, mods please move the thread.

I was wondering about the Fe iron number given in the VOA/UOA's as to whether or not there is or can be any differentiation between Fe2O3(not ferromagnetic red rust), FeO (ferromagnetic black rust) or Fe elemental iron, or do all three in all tests add to the total Fe reported.

Where the question comes from is could some types of oils maybe with a high sulfer content in O2 depleted oil bath environments lead to higher creation of FeO as might be seen in some gear oil UOA's for example. Thanks.

.

 

[JAG]

The tests do not differentiate between the iron atoms in those different molecules. The rust question is a good one. I don't have anything good to offer on that right now. Google it and you may find good info on it. If you do, please post it here.

 

[buster]

No idea, but a good question.

 

[bruce381]

most specto metal show all Fe
bruce

 

[Pablo]

Indeed you can see elevated Fe in oil samples in engines that are rarely run and otherwise have low wear - especially in condensing environments.

 

[Doug Hillary]

Hi,
Pablo - You said this:
"especially in condensing environments."

Please explain..................??

 

[Pablo]

Originally Posted By: Doug Hillary
Hi,
Pablo - You said this:
"especially in condensing environments."

Please explain..................??



Diurnal cycles with enough water vapor, and cool enough nights to produce visible moisture on relatively cool surfaces, even inside an engine.

http://www.microdaq.com/occ/lcd/external.php
http://www.astm.org/DIGITAL_LIBRARY/JOURNALS/TESTEVAL/PAGES/1232.htm

 

[Steve S]

Would these iron numbers "wear vs rust" be best determined through the trending of uoas? Winter wear vs summer wear for example?

 

[Doug Hillary]

Hi,
sorry to keep this going
Pablo - your statement above was;
"Indeed you can see elevated Fe in oil samples in engines that are rarely run and otherwise have low wear - especially in condensing environments."

Have you any "hard" and meaningful data supporting this? If so please share it with us.........................

IMHO:
bruce318 - I agree
Steve S - Yes - but I have some serious reservations about obtaining a truely meaningful result. Especially after operating vehicles in both Artic like and Tropical climates over some years

As we all know Fe traces at various levels can be a trait of VOAs

 

[Pablo]

Sure. Take a look at UOA section for a few years.

 

[Doug Hillary]

Hi,
Pablo - You said;
"Sure. Take a look at UOA section for a few years."

Really? That sort of comment does NOT back up your statement at all!!

 

[oilyriser]

I didn't see any evidence of rust on any of the iron parts of my first engine, after it was opened up for inspection, except on the outside. All the iron parts were clean and shiny. This doesn't rule out rust on the cylinder walls that gets scraped off later.

 

[Pablo]

If you aren't willing to look then that's fine. It's more than a casual observation. Especially in my region with folks who allow engines to sit several years vs. engines that are run.

 

[Pablo]

Originally Posted By: oilyriser
I didn't see any evidence of rust on any of the iron parts of my first engine, after it was opened up for inspection, except on the outside. All the iron parts were clean and shiny. This doesn't rule out rust on the cylinder walls that gets scraped off later.


I would say if you actually see iron oxide, it's pretty bad. No Doug, I won't have data for that.

 

[Doug Hillary]

Hi,
Pablo - To back up your earlier statement even a detailed Trend analysis of Fe in those engines covered by your comment;

"allow engines to sit several years vs. engines that are run."

would IMHO be difficult to accurately quantify

Like oilyriser has observed, rust is rarely evident. I have two V8 (GM/Ford) engines in various stages of storage at present. The one that has been idle the longest - since 2003 - has no visible corrosion

This is especially so in engine that are fired up for extremely casual use

I have never seen your stated Fe phenomenon in practice!

 

[oilyriser]

There might be a thing with cold starts, and condensed water mixing with lube in the cold cylinders, causing bad lubrication and increased wear. But this would not be iron oxide.

I did once find a fleck of rust caught in the pleats of my oil filter. The exhaust manifold probably gets very rusty inside, and maybe pieces of rust can get pushed back into the engine under certain conditions.

 

[RI_RS4]

I'm actually going to side with Pablo on this one.

Rather than call it "rust" why don't we call it oxidation? It's really not that hard to believe that an engine which sits for long enough to have the oil film flow down, evaporate, or be washed by condensation will experience some amount of metal oxidation.