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Discussion Starter · #1 ·
So what is your feeling on acceptable TBN for assessing if oil has any life left in it? Seems that TBN is consistent enough that you don't need the TAN number... unless you are chevron (link below)

Blackstone seems to say > 1
https://www.blackstone-labs.com/do-i-need-a-tbn/


Mobil Industrial Says >2
https://club.mobilindustrial.com/lu...e-oil-change-intervals-in-natural-gas-engines


Other sources hover around or > 3 (or 65% of starting TBN)
https://www.machinerylubrication.com/Read/2170/oil-drain-interval-tan-tbn
https://www.unitedlubes.com/why-united/news/total-base-number
http://pqiamerica.com/TBN.htm


Use TBN, TAN, oxidation, wear metals:
https://www.chevronlubricants.com/c...YSIS UNDERSTANDING TAN AND TBN 01-28-2019.pdf


marketing aside, acids and bases I get, and anything in the additives to help that I get. That is science I can attach to an oil.
 

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Given that we have a 6 month 6k mile interval which is probably safe for all except consistent severe service (e.g. predominantly city short trip and stop and go driving) if I had a TBN of 1 at the end of that period I would be concerned that repeatedly getting that low might be causing accelerated wear and probably try a shorter interval, like 3mo/3k and maybe switch oils.

If it were 2 at the end of 6 months I'd be comfortable but might shorten intervals to 4mo/4k

If it's 3 at the end of 6 months that's great but I wouldn't extend intervals.

I did a blackstone UOA but apparently they don't do TBN automatically (extra fee?) but this other person had TBN done in his analysis from NAPA:


Several sources say that an oil that starts out with an extra high TBN can cause increased ash deposits because the TBN additives leave ash when burned.

Found an informative series of videos that have very few views but I can't find anything wrong with what he's saying after verifying with other reputable sources, so it's food for thought.

 
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Discussion Starter · #3 · (Edited)
That's what I was thinking. And I think I was right to assume severe service at this stage.... (and feel bad I never did before... lol)

With Subie oil I am at a TBN of 3.x at 3K miles.... up to 6K jump is too much (if you look at my UOA's in there I went for the TBN always) Pretty sure subie starts above 8 (found a materials sheet somewhere)... just curious about some of the conflicting information. Will be pulling another sample shortly, will be subie oil, and will see if my driving style provides another consistent sample of the viscosity and TBN. So that will be factory fill, subie, subie over 9K miles

Switching to Castrol GTX Maganatec for 9K-12K (start TBN in the high 8s) but its a 6K oil not a 50K, I'm still under warranty, 6K is a fine place to start and don't want to to find and buy ultra High TBN oil (yet), and perhaps the additives will mitigate this some. The anti-oxidents?? and just the tiniest pinch of titanium... To be seen... how it wears and where the TBN and viscosity is in 3K and see if I can go to 4K or more. they should just add vitamin c and see what happens...

A lot of folks around here (my local geography) have to have a similar driving environment, does make me wonder what their TBN UOAs would reveal... different engine, but still.

The NAPA UOA referenced:
At 3K his first Napa sample shows a viscosity (7.x) and TBN (5.x) I haven't seen for 0w20 Subie.

(btw, his second is 5w/30 Rotella and they flag it for falling out of spec. If not a clerical error on his side....)

after-thought: then again, every 3K of a decent but relatively inexpensive oil is not so bad.... the numbers in the fall will be interesting.
 
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I always assume “severe service” applies unless one does mostly highway driving.

I have years of UAO numbers (Blackstone) in my files, don’t recall exact TBN numbers. Never have done TAN (no apparent need).

Mobil 1, Red Line, Amsoil, Brad Penn all check out OK up to ~16-18 months on TBN (for lower mileage cars (e.g., <10k miles/yr.), at ~10k miles acid creeps up).
 

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My use is severe of bumper to bumper in SoCal and on my UOAs where I paid for TAN, it didn't reveal much as part of the overall recommendation to go beyond 6k. TBN was always robust with plenty left over and 8k was within the oil's comfort zone.

Just for conversation, if you want to find a really stout TBN value in oil look for one that's ACEA A3/B4 which must have a minimum value of 10 v. SP which comes in around 7.8ish.

Those oils are really thick 30s or 40s but are monsters for TBN.
 

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Discussion Starter · #6 ·
for lower mileage cars
I started at near zero miles and out of the gate got a 3 TBN.

Yeah... bumper to bumper, or long slow crawls often on shorter trips, and multi short non-highway daily trips. Highway weekends though. Pre-covid, there would have been fewer daily neighborhood trips, but we are both home more often than not. Going back to a 2 on/3 remote work week and then a 3 on/2 remote work week soon and possibly permanently.

Under warranty, so sticking to 0w20 oils.

Not sure if TAN does make sense as well, as long as you have TBN the TAN would stay down... I think that is where the 3 metric comes from. Its inferred.

Below that and the acids start to win. A lot of acid already it would eat up the base and the number would be way low. Above 3, and it is enough base that acid is not an issue. (lol though Mobil says that number is a 2...)
 
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I started at near zero miles and out of the gate got a 3 TBN.

Yeah... bumper to bumper, or long slow crawls often on shorter trips, and multi short non-highway daily trips. Highway weekends though. Pre-covid, there would have been fewer daily neighborhood trips, but we are both home more often than not. Going back to a 2 on/3 remote work week and then a 3 on/2 remote work week soon and possibly permanently.

Under warranty, so sticking to 0w20 oils.

Not sure if TAN does make sense as well, as long as you have TBN the TAN would stay down... I think that is where the 3 metric comes from. Its inferred.

Below that and the acids start to win. A lot of acid already it would eat up the base and the number would be way low. Above 3, and it is enough base that acid is not an issue. (lol though Mobil says that number is a 2...)
By “lower mileage” I mean between oil changes, not vehicle mileage, just to clarify … 💡😎
 

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TBN is tricky because TBN depletion is not linear. One oil can start at 10 and another at 7 and the oil starting at 10 could end up at a 2 in less mileage in the same application than the one beginning at 7.

Also, keep in mind that there are different ASTM methods for the test. See the PQIA article you linked.

It should be noted that in addition to ASTM D2896, the TBN of a lubricant can be tested by the procedure detailed in ASTM D4739. There are subtle, yet important differences to consider when looking at TBN data from each. Technically, the primary differences between D4739 and D2896 are that whereas D4739 uses hydrochloric acid as the titrant, perchloric acid is used in D2896. In addition, they use different titration solvents.

Because hydrochloric acid is weaker than perchloric, D4739 is less effective than D2896 in titrating weak bases. This can result in what ASTM refers to as a “falsely exaggerated” or sometimes even “falsely understated” TBN’s for test method D4739. For these reasons, ASTM says “When the base number of the new oil is required as an expression of its manufactured quality, Test Method D 2896 is preferred, since it is known to titrate weak bases that this test method may or may not titrate reliably.” (See paragraph 5.3.1 in test method ASTM D4739.
Blackstone uses ASTM D4739.


I think OAI uses D2896 although I can't find it on their web site.
 

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Discussion Starter · #9 ·
Ty... and Oh... that is a headache...

"D4739 is less effective than D2896 in titrating weak bases. This can result in what ASTM refers to as a “falsely exaggerated” or sometimes even “falsely understated” TBN’s for test method D4739"

Now, words are funny... I think I read that as my 3.x is lower than what they report.... of course it IS a Monday and I am feeling somewhat negative about it.

I have to see if I can find some additional Blackstone UOAs with Subie oil and see how they rate and then maybe compare to other oils then (here and at Bob's I suppose).

yeah, there might be two draws for UOA next week....

Found D2896 here:
https://www.oaitesting.com/services.aspx


Edit: This might explain why Blackstone flag on a TBN of 1, if I have it in reverse. If my TBN is like a 5... (+2) then a 1 would be a 3....


Further Edit: That Anti-oxident joke I made before can actually be accounted for but only in D2896
 

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Ty... and Oh... that is a headache...

"D4739 is less effective than D2896 in titrating weak bases. This can result in what ASTM refers to as a “falsely exaggerated” or sometimes even “falsely understated” TBN’s for test method D4739"

Now, words are funny... I think I read that as my 3.x is lower than what they report.... of course it IS a Monday and I am feeling somewhat negative about it.

I have to see if I can find some additional Blackstone UOAs with Subie oil and see how they rate and then maybe compare to other oils then (here and at Bob's I suppose).

yeah, there might be two draws for UOA next week....

Found D2896 here:
https://www.oaitesting.com/services.aspx


Edit: This might explain why Blackstone flag on a TBN of 1, if I have it in reverse. If my TBN is like a 5... (+2) then a 1 would be a 3....


Further Edit: That Anti-oxident joke I made before can actually be accounted for but only in D2896
Welcome to splitting hairs with uoa's! 🤣
 

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That just brings a tear to my eye

It looks rather tasty with what looks like asada, creme fresh, cotija, tomatillo sauce and maybe that's chorizo and not asada.

Regardless, that's some fine looking vittles.
 

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Discussion Starter · #14 ·
Considering what is getting changed for the next oil, I will likely stay with Blackstone for now. This is the last subie fill for now as I switch. When I pull the GTX Magnatec I will pull both Blackstone and OAI and see what comes back for the fair going-forward comparison.

Until then, I think I prefer some souvlaki:

516745
 

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Marinated chicken kabobs, naan, tzatziki and Greek salad?
 

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Discussion Starter · #16 ·
beef souvlaki, tzatziki, a baby pita and feta... there might be things in front of it but it better be feta.
 

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New members discussing UOAs are so cute at that age.



Just give it time before he, like the rest of us, says, "I'm just going to have a chalupa and not worry about it.
There's a lot of truth to this.

If you are not trying to super mile your oil change interval and you are using any moden off the shelf full syn oil then your engine is well protected.

UOA's can give you a good idea of what an oil quality is after a set amount of miles but after that I would just save your money and drive with confidence.

Modern oils in the past 10 years have seen an exponential development in their protection and quality in virtually all aspects. It truly is amazing how well these oils can handle modern stresses and temp variances.

It is easy to become trapped into over thinking these metrics and just like within the medical field, simply knowing more can often become a bad thing.
 

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Discussion Starter · #18 ·
Overthinking is what forum life is all about!
 
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There is a sweet spot between over thinking and not thinking.

Edit: God grant me the serenity to accept the things I cannot change, courage to change the things I can, and the wisdom to know the difference.
 
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Discussion Starter · #20 ·
And then there is the desire to just understand... and get the metric right....

Knew there had to be an answer out there, and perhaps adding +2 to Blackstone's TBN is not a bad rule of thumb.

"This produces a number approximately 2 mg KOH/g LOWER than ASTM D 2896 for the same oil "

From this post

And while that links directly to the post it is an interesting thread from a long time ago referencing Chevron pages (but no links)

And also in there, seems like setting the TBN at >1 for Blackstone's was a bit arbitrary (one of the posters emailed them).
 
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