Originally Posted By: m37charlie
Assuming average speed (including idling and everything else) is 35mph, average mpg is 15mi/US gal, sump 10 qt, then 42k mi = 1200 hrs, oil consumption is 0.225gm/kwh and OSF is 3.04. Numbers are VERY good for an OSF that high. My iron was 36ppm and TBN 12.4 for a 500hr run with OSF about 1.2.
If you never change your oil again OSF will level off at 4.5 for you (1/R, R = specific oil consumption rate in gm/kwh)
Charlie
I cannot remember my exact sump capacity (its been a while lol) but 10 or 11 qts is right on. Average speed I do not know but my guess would be around 40 or 45. Most of my driving is between 55-60 and I run 80 on the interstate usually but only about once a week besides the 6 miles I jump on it for work 3 days a week.
Average fuel economy is about 17.5
Originally Posted By: dnewton3
Originally Posted By: 4x4le
Originally Posted By: dnewton3
Wow! I applaud the concept here; using a lube until it's fit to be condemned!
That being said, unfortunately, we're going to have to help the OP establish his own condemnation points, because neither GM or Isuzu has set any limits. There are many other makers that do set limits, and we can perhaps glean some insight from them:
(see page 11 of this report, which is page 16 of the PDF as I see it); copy/paste into your browser
http://www.calrecycle.ca.gov/Publications/Documents/UsedOil%5C2008020.pdf
Given this info, I'd say 100ppm Fe is a safe limit (noting that Cummins uses a range from 75-100, but all others are 100 or above, I'd say the industry overall is 100ppm or higher). And don't loose sight of the fact that while you have 32ppm of Fe, that's spread over 43k miles! So your Fe wear rate is LESS THAN 1PPM/1K MILES!
As for the other metals such as Cu, Pb, etc, you're simply no where near anything even remotely condemn-able whatsoever.
The contamination is practically nil; fuel, water, Si and such all well in control.
The other lube properties such as Vis and oxidation OK also.
Kschachn also brings up a good point; just because Fe may reach some arbitrary mark, it needs to be understood in context. If all the other parameters stay well in control, and Fe is known to be cumulative, then seeing it escalate in a controlled manner should not automatically cause an OCI. If you were seeing an escalation of not just Fe, but Cu and Pb, then I'd say it would be a clue to consider an OCI. But all other factos (the other wear metals) are essentially at or near a "zero ppm per mile" state. So the fact that one metal will track with accumulation is not a cause for an OCI, but rather just the affirmation that things are completely as expected and operating in a near-perfect state.
In fact, the REAL DETERMINING FACTOR should not be a ppm count, but a "wear rate". The time to starting paying closer attention is when the wear rates start to tick upwards. Right now you're under 1ppm/1k miles; that's absurdly good. If you got to 2ppm/1k miles, it would be time to cautious, and at 3ppm/1k miles, I'd say time for an OCI.
At this point I would say you're not even close to having to dump the lube.
I want to commend you on actually using your brain and solid logic in managing your maintenance program. This is how it is done in industries that have multi-million dollars of machines to care for. They don't hit the panic button when some arbitrary maker rolls onto the odometer or hour meter. Rather, they manage the lube based upon contamination and wear rates. Right now, your contamination is zip and your wear rates are crazy low. There is ZERO REASON TO CHANGE THIS OIL, and probably won't be for a while.
Also, you don't mention it other than changing the filter a few time, but are you using bypass filtration? Just curious. Normally I'd say you would almost have to be to get such low soot in this duration, but because you've blocked EGR and deleted regens, this engine is essentially running very clean and so it's possible to get these results without BP filters perhaps.
Is this a good lube? Sure. But it's also in a Dmax; one of the best wearing diesel engines ever made.
Congratulations, sir. Out of 61,000+ BITOGers, you're one of only a handful that actually understand how to properly maintain a piece of equipment with your brain and not your emotions. I cannot express this enough: you impress me with your logical approach; one that I preach about all the time and typically falls on deaf ears around here. Only about 1:10,000 BITOGers understands what you are doing and why.
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Thanks for the input. I do not have any bypass filtration or magnets. The part I need "talked down off the bridge" about is sludge. Co workers seem to be worried that sludge will be a problem. I would think TAN would have to raise for that to be a problem or some other number get out of check but I have nothing solid to reply with.
Sludge is essentially the evil end of heavy oxidation and excessive soot; neither of which your oil samples exhibit. TAN has nothing to do with it.
You may come down off the bridge now.
Im coming down
