3 off Crown Vic, 5W20, Las Vegas, 15,000 miles

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I recently read about a spike in fe right after oil change as additive break\mesh in, then a decrease over the life and then it begins to rise again as we see here as it near life end, you see,the increase at 10k prob reaching the sweet spot around 10k
 
The way I understand the testing process was that each of the mileage runs were not conducted on the same oil. The oil was run for 3k drained and sampled and refilled, then 5k drain sample, et seq. all the way to 15k which is why the iron numbers went down, as otherwise it wouldn't make any sense for 100 ppm of iron to just disappear. I might be mistaken but that's my takeaway from the article and test procedure.
 
If you performed a UOA the day after changing your car or truck's oil, you would find a sharp contrast to the VOA of the new oil.
Could that be used as evidence that the new oil is causing excessive wear?
What would one day old engine look like in a UOA after a succession of extended oil changes?
You might even find some of that missing Fe.
 
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Originally Posted By: FlyNavyP3
The way I understand the testing process was that each of the mileage runs were not conducted on the same oil. The oil was run for 3k drained and sampled and refilled, then 5k drain sample, et seq. all the way to 15k which is why the iron numbers went down, as otherwise it wouldn't make any sense for 100 ppm of iron to just disappear. I might be mistaken but that's my takeaway from the article and test procedure.


Yes that's true
 
Originally Posted By: userfriendly
Extend away then using the BITOG standard of wear metal evidence based UOAs and ignoring the condition of the lubricant.

Most people doing UOAs here aren't just condemning based on wear metals. There are several things one can take into account, and most do. I don't think I've seen a lot of posters wait until they get an arbitrary 150 ppm of Fe, yet ignore viscosity, TBN, and so forth.
 
I addition to my statement you quoted, some oil companies sell oil change intervals using UOA low wear metal content as evidence to the superiority of their product.
Go 25K miles, ignore the sludge in the pan and plugged oil filter and just go off the UOA wear metals, is basically what they are stating.
Double or triple the manufactures' oil change interval & save money.
 
Originally Posted By: userfriendly
Extend away then using the BITOG standard of wear metal evidence based UOAs and ignoring the condition of the lubricant.
At the very least, you will burn more in fuel than savings on motor oil. Maybe add a few more minutes on that long slow grade.
At worst, you will trash the engine and ancillary equipment like the air pump.
But have at it, each to his or her own.

Here is a video from Chevron-Caltex on UOAs.
The question asked by Shannow was; Where did the Fe go?

https://www.youtube.com/watch?v=V6XIPDoP_pU


I think you're selling most of the extended oci people short. There may be plenty of talk regarding wear metals here, but I think that those who extend and sample are looking at the oil condition to see what their next move should be.

I completely agree with you about the dangers of over doing it and the loss of fuel economy when oil thickens too much. But you would have to go to great lengths and ignore the sample reports to develop the mess you see in the videos posted. Those videos represent total disregard or total ignorance of maintenance practices.
 
You are absolutely right DustyRoads.
You are not my target audience, but those who ONLY look at wear metal levels in UOAs, and make conclusions without looking at the bigger picture.
There is a shift point when an engine oil is dropping wear metals out of suspension and into sludge.
There is also a shift point where fuel economy drops below the cost of an oil change, if we are talking economics.
Now go to the other threads in this section and pick out the posts that convey the wrong messages.
The TBN/TAN and viscosity relationship from VOA has changed drastically, but "we think you could extend the ODI XX more miles", etc.
Once again, using said wear metals for confirmation.
 
Yep, you guys get it...

I posted the table in the thread, as that paper was being used to promote extended oil changes on wear metals only, along with statements that TBN, acids, viscosity and all of the other comparators that are used are irrelevant (summarily dismissed)

Because
a) used oils made tribofilms sooner than new...therefore older oil is better
b) the wear metals are the absolute measure of wear performance.

Most BITOGers who do UOA and longer drains are smarter than that.
 
Originally Posted By: userfriendly
I addition to my statement you quoted, some oil companies sell oil change intervals using UOA low wear metal content as evidence to the superiority of their product.

Of course, there always is a marketing aspect where someone can cherry pick a data point or two and try to use that to show some "superiority" of their product. That being said, there are certainly instances where an OEM OCI can easily be doubled or tripled with an appropriate product. In other scenarios, that's not feasible.

Our taxis going double GM's 3,000 mile severe service interval back in the day was feasible, even with conventional; more could have been possible with a modern, extended drain oil. With my Audi 200 Turbo, with a 12,500 km severe service interval, which was optimistic as it was, things wouldn't be so straightforward.
 
Originally Posted By: userfriendly
You are absolutely right DustyRoads.
You are not my target audience, but those who ONLY look at wear metal levels in UOAs, and make conclusions without looking at the bigger picture.
There is a shift point when an engine oil is dropping wear metals out of suspension and into sludge.
There is also a shift point where fuel economy drops below the cost of an oil change, if we are talking economics.
Now go to the other threads in this section and pick out the posts that convey the wrong messages.
The TBN/TAN and viscosity relationship from VOA has changed drastically, but "we think you could extend the ODI XX more miles", etc.
Once again, using said wear metals for confirmation.


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Agreed. As you've already mentioned in other posts, there's the need for oil to be in grade for uber cold starts, too. You're making good points for all to consider.
 
nice find, I'll have to read that thoroughly.

but I did see this, for the Monograde users:
Quote:
The use of multigrade oil reduces deposit formation, improves engine cranking in low temperature conditions, and increase sengine durability by maintaining lubrication during high temperature operating conditions. Since multigrade oils have been shown to provide approximately 30 percent lower oil consumption, compared with monograde oils, it is important to use multigrade oils. While the preferred viscosity grade is 15W-40, lower viscosity multigrades can be used in colder climates.
 
I tried to white that out on the screen, but you found it anyway.
SAE 15W40 vs SAE 40 of the same KV100C would have a lower HTHS.
Conversely, if the HTHS were the same, the KV100C viscosity would be lower in the SAE 40.
This bulletin was originally published around 2004 and updated every few years since.
Oil consumption 15W40 vs SAE 30, would depend on whether the 30 was a thick one and the 15W40 a thin one.
I've tried both in a 0W20 Toyota engine and observed 500ML/16K km oil consumption.
 
Garak; You posted in an earlier thread, that your dad's taxis were LPG fuelled. That is why you could extend the oil drain interval times 2 or 3.
 
Yes, that certainly helped. Other things contribute, too, like the oil never cooling down. They're certainly not short tripped.
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But, having no real fuel dilution is amazingly helpful.
 
Thanks. I always hate it when someone here posted pics, but their online photo account has been disabled and there is no image to see.

Originally Posted By: Shannow

Taken the image out of photobucket...
 
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