Oxidation

[2009Edge]

I use AMSOIL 0W-20 in my 2009 Edge. My oil sample analysis indicated that oxidation is severely high. I changed the oil and filters.
I had 14,000 on this oil, everything else was in specification.
Most of this mileage was long trips. The last trip was from Texas to California and back. I saw the onboard exterior temperature indicator reach 110.

What could cause the oxidation to jump?

I have performed OCI's in the past using the same oil and interval.

 

[Brons2]

What does the rest of the analysis say? Amsoil starts off with fairly high 'oxidation' to begin with. It's the delta between the beginning and ending numbers you are worried about, not the overall number.

 

[ltslimjim]

^Exactly. Find the starting number and see if it's truly abnormal for Amsoil. 0w-20 is probably group IV + V base, which makes sense for TAN numbers. Is Oxidation(higher?) something that goes hand in hand with base oils from those groups?

 

[dparm]

Are you getting any fuel dilution?

 

[Pablo]

Originally Posted By: Brons2
What does the rest of the analysis say? Amsoil starts off with fairly high 'oxidation' to begin with. It's the delta between the beginning and ending numbers you are worried about, not the overall number.


YES.

(You guys are awesome. You get it)

OP - Please post your entire UOA.

 

[2009Edge]

Infrared results indicate OXIDATION is SEVERELY HIGH; Total Base Number is SIGNIFICANTLY LOW; Abrasives (silicon/dirt) are at a MINOR LEVEL; FUEL DILUTION is at a MINOR LEVEL; FUEL DILUTION possibly caused by excessive idling.

Sample Analysis
PPM - Iron 13; Chromium 0; Nickel 1; Aluminum 3; Copper 33; Lead; 0 Cadmium 0; Silver 0; Vanadium 0; Silicon 25; Sodium 19; Potassium 5; Titanium 0; Molybdenum 2; Antimony 0; Manganese 8; Lithium 0; Boron 6; Magnesium 10; Calcium 2825; Barium 3; Phosphorous 560; Zink 630.
Viscosity100 cSt 9.6; Bade Number 2.49 mg KOH/g; Oxidation 60 abs/cm; Nitration 33 abs/cm; Fuel Dilution %Vol 2.2 GC.

Hope this helps.

Question is: Does operating in a hot environment such as NM, AZ, NV and Calif deserts affect oxidation?

 

[ltslimjim]

^I'd say if you are running the AC full blast, mid day while idling, that you may see a HTHS scenario occur depending on your vehicle. I'm not educated enough to know about what all causing the oxidizing of the oil, but one must establish where is the level in it's virgin state?

If you are worried, as this appears to be the previous 0w20 Amsoil formulation, sample and send in a Virgin of what you proceed to put into this application next, use the same company you did and that had these numbers(just dont include buying the TBN test as it is useless to you since we already know the TBN of Amsoil 0w-20 ASM)...then get a UOA performed again and compare the post oxidation/nitration to the Virgin oil analysis.

 

[Jim Allen]

2009 Edge- Just keep some perspective. No matter how good the oil, it will eventually have to be changed. Engine design parameters and/or driving scenarios will shorten the OCI in some cars and lengthen it in other. It will be what it will be and that's why the UOAs are useful to help you gauge how long you can go in your particular combination of circumstances. I agree about the virgin test... that's always a good place to start.

I don't think the base number, at 2.49, is all that low considering it's 14K miles but I don't know what the starting TBN is for whichever series Amsoil it was.

Really, no drama here. The oil is used up, change it and run the same interval next time and sample again. You got the full good out of it this time. Be happy!

 

[MolaKule]

Some oxides come from the NOx created during the combustion process and some come from the oxygen molecules in the additives or base oils.

As others have stated, always compare a new oil sample from the same lab and then you can compare your used oil against the VOA.

The oil performed well, viscosity was stable, and it's time for an oil change.

 

[OldCowboy]

According to the VOA I had performed by Polaris Labs ( Amsoil 0W20 VOA ) this oil starts off with an oxidation number of 47. An increase of 13 points doesn't seem excessive to me.