Amsoil SS 0w-30 1.4L Tur 2014 Chevy Cruz 20k OCI

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Originally Posted By: kschachn
Originally Posted By: Artem
Well said. Definitely hard to decide what I want in an oil. Sure TBN retention sounds good on paper but if it ain't eating up the acid in its effort to retain said TBN for 20,000 miles then the oil ends up being acidic as can be at the end but still TBN leftover. LOL.
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Seems the best oil is an oil that is designed for a set interval and it goes to work 100% the entire time and is toast when it's designed to be toast and then you dump it in favor of fresh Lube and additives.

I don't understand what you're saying here. If there is acid entering the oil then it will deplete the TBN. When you test for the TBN you titrate it using an acid. Either it has neutralizing capability or it doesn't.


You will titrate it with a strong acid. It is possible for it to react with strong acids during titration and not weak acids inside the engine.

Does TBN tell you everything?

Is TBN completely useless?

Those are both absolute statements which I would disagree with. It seems like a very useful test that has caveats like anything else.
 
So if I’m running MobilGard starting with a 60 TBN … and after some hours a sample is 52 TBN …
I’m supposed to run TAN ?
 
As far as I can tell from UOAs the TBN drops more rapidly initially, to around 2.5, and then decreases more slowly.

I do not expect the rate of acid formation to decrease later in oil service. I expect it to remain fairly constant. Yet the rate of TBN decrease seems to go down late in the OCI. This suggests acid is not being neutralized as well.

If your TBN is 3 or higher there is no point of doing a TAN test. If you are running an extended OCI and the TBN is below 2 it might be useful to get a TAN test as well.
 
Originally Posted By: camrydriver111
As far as I can tell from UOAs the TBN drops more rapidly initially, to around 2.5, and then decreases more slowly

One would think that is due to using two (or more) different buffers.
 
But what about the good ol' TBN / TAN crossover = condemnation point?

How much acid (TAN) is too much?

Seems to me that either the numbers are totally useless nonsense or there's more to this equation.

 
I love the discussion. I'm sure it could go on for more debate about TBN & TAN... ect. All I know is, compared to the Universal Avg for this engine, my extended OCI on this oil did amazingly well as stated by the actual results. By line item, it's factual to say the engine had minimal wear metals and add pack was still quite strong (moly, Boron, Calcium, Phos, & zinc)... with an almost 2.0 on the TBN...flashpoint was strong... fuel dilution very low, and the viscosity stayed in acceptable range. Not that I care to really push it much farther than this.. and likely won't too often as the miles continue to creep up over 100k... I will run one more 20k OCI with the Pennzoil Ultra Platinum just for comparison sake vs. Amsoil. Outside of that, I will likely go back down to the 10k OCI. I can surely afford the few extra bucks for the oil and filter on that OCI routine... plus extra insurance and peace of mind that comes with a very solid oil and filter change at 10k.

Thanks for everyone's comments. I appreciate the expertise and commentary! Looking forward to reading others who submit their lab results and learning more from them!!!
 
Originally Posted By: Artem
But what about the good ol' TBN / TAN crossover = condemnation point?

How much acid (TAN) is too much?

Seems to me that either the numbers are totally useless nonsense or there's more to this equation.




In my opinion, that oil is spent. From what I understand, if TAN is above TBN, then no further use is suggested. Even if TAN is approaching TBN or close to it/ready to cross, one should discontinue its use.

I think your example shows perfectly, that TBN numbers mean nothing without TAN numbers. If you had only opted for TBN in your analysis, you would think the oil is still good/acceptable for further use based on the TBN number.
I am surprised at Blackstone's comments about further use?

I am no expert, but that is what I got from all the info provided that talks about TBN and TAN.
 
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Oh I agree. Perhaps they (Blackstone) know something that we don't in regards to TBN / TAN condemnation limits?

How about this report from 11-5-2011.




I actually did end up going further to 12,000 miles but on Amsoil's Signature Series oil and then the car was totaled @ 150k miles with a Spotless engine from what I can see thru the fill hole.

After all these years and many UOA reports, I still don't know what to do about this TAN / TBN crossover question. Lol.
 
Originally Posted By: WobblyElvis
I had a UOA done by Blackstone and the TBN was 1.0 yet they still suggested I could go another thousand miles next time.


Probably since TBN depletion is not linear.

As far as the TAN question, there is a certain amount in a virgin sample so IMO that needs to be taken into account.
 
Originally Posted By: WobblyElvis
I had a UOA done by Blackstone and the TBN was 1.0 yet they still suggested I could go another thousand miles next time.


Sounds like they want you to squeeze every extra penny out of the oil. I thought 1.0 was their condemnation level? I would ignore their suggestion.
 
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