2008 Forester, 15020 Miles, Subaru 5W-30 Syn

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Al

Joined
Jun 8, 2002
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Elizabethtown, Pa
159,420 on the clock 50/50 Highway/local. Subaru Filter replaced midway thru run. Oil use including filter change was 2.5 quarts. I wasn't going to do TBN but to prove to to myself that TBN is not required I got it.

Vehicle had HG changed at 125K miles. Timing belt, WP,idlers, and tensioner changed at 110K miles. I plan on running this thing til it (or me) dies. Great car. Its the 2.5NA engine

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Looks good. 15-18K OCI would be good for you assuming you are changing the oil filter at the 7-9K mark. The grade was lower but that is to be expected. Nice report.
 
Am I reading that right - single digit wear with 15k on a 'non long-drain' synthetic oil?

Wow. just wow!
 
3 quarts of makeup oil added... Which will dilute wear metals and also boost TBN.
 
Originally Posted By: ryanm8
3 quarts of makeup oil added... Which will dilute wear metals and also boost TBN.
True. All the more reason to longer. And not worry about TBN. Like I said...I never saw a TBN out of specs in 15 years I have been here.
 
Originally Posted By: Al
Originally Posted By: ryanm8
3 quarts of makeup oil added... Which will dilute wear metals and also boost TBN.
True. All the more reason to longer. And not worry about TBN. Like I said...I never saw a TBN out of specs in 15 years I have been here.


But what about TAN?
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Originally Posted By: ryanm8

But what about TAN?
smile.gif


LOL..who cares
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I think as long as UOA turn out great (the proof is in the pudding) TBN is a waste of money. But lets face it..UOAs are in many cases a waste of money. For me its entertaining to do a long haul and check the results.
 
Originally Posted By: ryanm8
3 quarts of makeup oil added... Which will dilute wear metals and also boost TBN.


Dilute wear metals ? ......... not true.
Boost TBN (and add pack) ? ...... Yes.
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OP,
Nice UOA you have.
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Ever consider throwing in an xW40?
 
Ever consider throwing in an xW40? [/quote]
Yea its a thought. IO may use the 40 wt. as makeup....as a minimum this time. Next time I'll add 2 quarts of XW-40.
Thanks for the reminder.
 
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Originally Posted By: zeng
Originally Posted By: ryanm8
3 quarts of makeup oil added... Which will dilute wear metals and also boost TBN.


Dilute wear metals ? ......... not true.
Boost TBN (and add pack) ? ...... Yes.
whistle.gif


OP,
Nice UOA you have.
thumbsup2.gif

Ever consider throwing in an xW40?


If you have a fluid with 20ppm of iron, and you add 3 quarts of fluid with 0 ppm of iron, you are telling me the resulting fluid still has 20 ppm of iron?
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People get too caught up in UOA results on this site. They are one tool in the toolbox. You can run an oil out to 30k and the wear metals will probably be fine. The wear metals don't tell you anything about sludge or oil longevity. That is why TBN/TAN are important.
 
Originally Posted By: ryanm8
If you have a fluid with 20ppm of iron, and you add 3 quarts of fluid with 0 ppm of iron, you are telling me the resulting fluid still has 20 ppm of iron?
smile.gif



5 quarts has 20ppm. It burns a quart, if you analyzed it now at 4 quarts the ppm would be higher. Add a quart and it goes back to 20ppm. I think.
 
Originally Posted By: AZjeff
Originally Posted By: ryanm8
If you have a fluid with 20ppm of iron, and you add 3 quarts of fluid with 0 ppm of iron, you are telling me the resulting fluid still has 20 ppm of iron?
smile.gif



5 quarts has 20ppm. It burns a quart, if you analyzed it now at 4 quarts the ppm would be higher. Add a quart and it goes back to 20ppm. I think.


Ppm won't change from burning a quart. But adding fresh oil will lower it.
 
Originally Posted By: AZjeff
Originally Posted By: ryanm8
If you have a fluid with 20ppm of iron, and you add 3 quarts of fluid with 0 ppm of iron, you are telling me the resulting fluid still has 20 ppm of iron?
smile.gif



5 quarts has 20ppm. It burns a quart, if you analyzed it now at 4 quarts the ppm would be higher. Add a quart and it goes back to 20ppm. I think.

When you burn a quart the iron will go out with it. The remaining oil will still be 20 ppm. But when you add the quart it is now 16 ppm. So I agree that had it not burned oil the ppm would be a lot higher.

But I won't agree that TBN is a problem and likely never is. I would like to see 3 UOA's in the many thousands here where TBN was 1.
 
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Blackstone considers a TBN under 1.0 to be too low, but that isn't universally agreed upon. Many consider < 2.0 too low and some even consider < 3.0.

I do think though that the oil will likely be oxidized before reaching a TBN of 1.0. But if TBN is no longer decreasing, it's no longer neutralizing acids, so TAN will start to skyrocket and then you get sludge.

This probably won't show up in wear metals in a UOA. More likely would be increased oil consumption and sludge over time.
 
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