Mobil 1 5w-30 5.2k miles; Toyota 4.0L v-6

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There was a dude on here with a 454 in a Chevy Suburban that had 6-7 years on an oil change, the oil was still perfectly fine.

I have an old Farmall H that has had the same 15W-40 oil in the sump for over 15 years.
It gets used 1-2 hours per year, twice a year up to full operating temp. I see no good reason to change it.
Love you man! Keep up the good work.
 

ZeeOSix

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Thanks for your feedback. The only concern I had with the report was the TBN number. If TBN depletion is linear, then I would be consider maybe stretching the OCI. However after reviewing your comments about the possible inaccuracy of TBN data, I'll probably cut back oil changes to 1.5 yrs.
I'm not taking the chance of running aground on a "sand bar"!
Does oil TBN degrade from time while just sitting, or is the depletion more a function of the miles on the oil?

Would the same oil that is 2 years old with only 1000 mile on it have less TBN than if it was 1 year old with the same 1000 miles on it?
 
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Factory Fill After 4 Years and 9,000 mi.

 
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Factory Fill After 4 Years and 9,000 mi.

Wow.
 
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D4739 TBN simply isn't all.thst indicative anymore. It can be as much as 3.0 off a D2896 test. It doesn't seem to pick up the newer nonmetallic organic additives.
You can often go thousands of miles after it bottoms before acids start to tick up. Many major engine manufacturers don't even have a condemnation limit for it anymore. With the extrenely low sulfur fuel the hard base simple isn't that important. As long as you have it you know your safe but if you are trying to avoid discarding lubricant early monitoring oxidation and nitration seems more useful.
D2896 is recommended by ASTM only for virgin samples:
Because hydrochloric acid is weaker than perchloric acid, 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”. For these reasons, ASTM says:
When the base number of the new oil is required as an expression of its manufactured quality,
Test Method D2896 is preferred, since it is known to titrate weak bases that this test method may
or may not titrate reliably.

D4739 TBN is preferred for used oil analysis:
When the base number of in-service or at-term oil is required, D4739 is preferred in many
cases, specifically for internal combustion engine oils, weakly basic degradation products are
possible. Test method D2896 will titrate these, thus giving false value of essential basicity. When
a loss of a base number value as an oil proceeds in service is required, then test method D4739
should be used.

And because you can't compare the two methods, it's necessary to use the same one when comparing a used sample to its virgin values. That's why more labs settle on D4739 for both.
 

dnewton3

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1) TBN degradation is not linear
2) TBN degradation has not shown to be inversely proprotional to TAN rise
3) The TBN/TAN relationship has been shown, repeatedly in thousand of UOAs, to have no direct effect on wear in modern engines using modern fuels. TBN/TAN "crossover" was historically used as a point to change oil, but that "crossover" has shown absolutely no correlation to wear trends, and therefore is an "old skool" means of thinking about oil changes and has no relevance today
4) TBN should no longer be used as a condemantion limit; it is merely a characteristic to track as a means of looking for wear-trend shifts


There's nothing in this UOA that would be surprising. Two years is not a problem. I've gone three years on many OCI in low-mileage use; other people have gone as many as five that I've seen in UOAs. As others have said, the type of use in those low miles is probably more important than the miles.
 
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1) TBN degradation is not linear
2) TBN degradation has not shown to be inversely proprotional to TAN rise
3) The TBN/TAN relationship has been shown, repeatedly in thousand of UOAs, to have no direct effect on wear in modern engines using modern fuels. TBN/TAN "crossover" was historically used as a point to change oil, but that "crossover" has shown absolutely no correlation to wear trends, and therefore is an "old skool" means of thinking about oil changes and has no relevance today
4) TBN should no longer be used as a condemantion limit; it is merely a characteristic to track as a means of looking for wear-trend shifts.

Now wait just a minute there, guy…

What if the Oil Bob guys at that old school weren’t looking at engine wear data when making an educated guess on oil life? What if their way of thinking was…

“Ok, so this oil started out with TBN additives (the good guys) @ 2x that of the natural acidic nature of all these chemicals blended together = TAN (the bad guys). When the ratio decreases to a 1:1 and the bad guys are now going to start outnumbering the good guys, it’s time to call it done and end this battle before someone becomes a loser”

👆🏻

There’s nothing wrong with that conclusion, in my opinion. I’m sure the oil does start to degrade from that point and is now no longer at acceptable performance levels that the Oil Bob guys were willing to accept, because their goal was… say… 95% or better.

This worked just fine all these years, hasn’t it? Too many million mile owners shouting from their worn down drivers cushion “I’ve been changing the oil every 3,000 miles on the dot, sonny boy” 😤🤬

Fast forward and a new generation of Oil Bob’s are born and these guys are examining thousands of UOA data from thousands of different engines and driving conditions and are going based off of WEAR.

“Who cares if there’s only 1.0tbn good guy(s) left vs 4-5tan bad guys if in the end, this last Spartan is their best fighter and he does some Jackie Chan stunt and takes out all the bad guys and WINS!!!” (Think, zero engine wear increase @ 10,000 miles (new age) on the oil vs dumping it at 3,000 miles (old skool)

I hope all of that made SOME sense. It did in my head. 😶‍🌫️ 😎 🤪
 
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3) The TBN/TAN relationship has been shown, repeatedly in thousand of UOAs, to have no direct effect on wear in modern engines using modern fuels. TBN/TAN "crossover" was historically used as a point to change oil, but that "crossover" has shown absolutely no correlation to wear trends, and therefore is an "old skool" means of thinking about oil changes and has no relevance today

honest question, barring metallic wear, what does high TAN start to do to non-metallic parts like seals, sealants, and gaskets?
 
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Now wait just a minute there, guy…

What if the Oil Bob guys at that old school weren’t looking at engine wear data when making an educated guess on oil life? What if their way of thinking was…

“Ok, so this oil started out with TBN additives (the good guys) @ 2x that of the natural acidic nature of all these chemicals blended together = TAN (the bad guys). When the ratio decreases to a 1:1 and the bad guys are now going to start outnumbering the good guys, it’s time to call it done and end this battle before someone becomes a loser”

👆🏻

There’s nothing wrong with that conclusion, in my opinion. I’m sure the oil does start to degrade from that point and is now no longer at acceptable performance levels that the Oil Bob guys were willing to accept, because their goal was… say… 95% or better.

This worked just fine all these years, hasn’t it? Too many million mile owners shouting from their worn down drivers cushion “I’ve been changing the oil every 3,000 miles on the dot, sonny boy” 😤🤬

Fast forward and a new generation of Oil Bob’s are born and these guys are examining thousands of UOA data from thousands of different engines and driving conditions and are going based off of WEAR.

“Who cares if there’s only 1.0tbn good guy(s) left vs 4-5tan bad guys if in the end, this last Spartan is their best fighter and he does some Jackie Chan stunt and takes out all the bad guys and WINS!!!” (Think, zero engine wear increase @ 10,000 miles (new age) on the oil vs dumping it at 3,000 miles (old skool)

I hope all of that made SOME sense. It did in my head. 😶‍🌫️ 😎 🤪

The major engine manufacturers have done away with it because it doesn't track with TAN, Oxidation, Nitration or Sulfation with modern fuels. Now throw in the fact that Hard Base has went from 90% to 70% of Total Base in some cases and you get really odd results like oils dropping 75% TBN the first 10,000 mi followed by 0% drop in the next 20,000 mi. Many extended drain oils will show TBN well under 1.0 TBN in Manufacturer approval testing. They don't care about that because it doesn't matter as long as Oxidation, Nitration, Sulfation, Soot and Insolubles are held in ch
 
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The major engine manufacturers have done away with it because it doesn't track with TAN, Oxidation, Nitration or Sulfation with modern fuels. Now throw in the fact that Hard Base has went from 90% to 70% of Total Base in some cases and you get really odd results like oils dropping 75% TBN the first 10,000 mi followed by 0% drop in the next 20,000 mi. Many extended drain oils will show TBN well under 1.0 TBN in Manufacturer approval testing. They don't care about that because it doesn't matter as long as Oxidation, Nitration, Sulfation, Soot and Insolubles are held in ch

Nicely said. 👍🏼
 

dnewton3

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honest question, barring metallic wear, what does high TAN start to do to non-metallic parts like seals, sealants, and gaskets?
I understand your basic question, but the reality is that it's WAY to vague to give a detailed answer.

There are many acids. There are many bases. There are many, many, many different chemicals used in "seals, sealants, and gaskets".

I'm not a chemist. But I'm smart enough to know that some acids may react poorly with some seals and gaskets, or may not react at all, depending upon the chemistry of the acid and materials.

The answer to your question is "it depends ...." The answer is a vague as your question.
 
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