I printed this article, Used Oil Analysis: How to decide what is normal some time ago but never got a chance to read it until recently. It's from another forum that is mentioned here often enough:

https://www.bobistheoilguy.com/used-...hat-is-normal/



I'm presenting this as a means to get the conversation going about the duration of OCIs and present the facts I learned from it. The info that Dave Newton, a user here, gathered from his study of UOAs was very interesting. I will copy and paste from the article to present the summaries I want to show. He gets into statistics some which is over my head but I let him explain it as the article goes. He only discusses wear metals which he states are the results and not the inputs. Inputs like the "elemental inputs such as (calcium, magnesium, phosphorus, boron, etc)" and physical properties such as flash point and viscosity, etc. which the oil manufacturers manipulate and control. So in his own words, "we’ll focus on the wear metals, because they are the “tellers of tales”; they let us know how much wear has occurred, and can allow us to have reasonable understanding of how much more might occur, should an OCI be extended. In short, manipulated physical fluid properties and additive-package criteria are inputs, whereas wear-data results are outputs."



He does talk about the the slight shift in wear metals in the Ford 3.0L OHV gasoline V-6 after the change to a name brand synthetic oil and a premium oil filter from conventional oil and a off the shelf typical oil filter. Two metals went up and three metals came down. I'll let you guys read the article to get the full feel for it. Basically, that for a 5k OCI, the change was so small for that interval that it didn't offer an advantage to paying for the premium oil and filter. I added this here not as a main point to this thread but because it is in this article, I figured I would mention this. It makes you think what would happen if you could compare the UOAs of 6.7s running conventional oil with the UOAs of 6.7s running synthetics. What would that show or be revealed from that comparison? I say this as a fan of synthetic oils and the concept of using synthetic.



The next engine he talks about is the Ford 4.6L “modular” gasoline V-8. There are five years of UOAs and over 500 reports that went into these numbers there. This is where I found the trend for iron wear particles to be interesting and one of my major points for posting this:

"Here is where Fe wear gets really interesting. What happens if we break down the data from mass population, and get into directed duration sub-groups? I pulled out samples within the UOAs and found the average Fe wear was thus:

UOA avg. Duration 3K 5K 7K 10K

Fe ppm / 1k miles 3.2 2.5 2.5 2.3

It is in fact true to say that when you change oil frequently the UOA will exhibit a higher Fe wear metal count. There are two reasonable explanations to this phenomenon of elevated wear metals shortly after an OCI; residual oil and tribo-chemical interaction. When you change oil, no matter how much you “drip-drip-drip” the oil into the catch basin, there is always a moderate amount left in the engine. Ryan Stark of Blackstone estimates up to 20% of the old oil remains, more or less, depending upon the unique traits of each piece of equipment. So, when you begin your new OCI, you really are not starting at zero ppm. Additionally, there is indication that wear is elevated after each OCI because of chemical reactions of fresh additive packages. This claim is supported via an SAE study done by Ford and Conoco (ref #1) that surmised this very phenomenon, and additionally refers to a former study of the same conclusion predating it."



The next engine he talks about is the GM-Isuzu 6.6L Duramax diesel V-8. The data from this engine shows the same trend as above when it comes to iron wear particles decreasing when going out further with the OCI. I'll let you guys read the article but to summarize it:

"I wanted to know how oil lifecycle affected wear rates, so I looked at three sub-groups; 3.5k miles, 7.5k miles, 11.5k miles. And, again, higher Fe wear rates are revealed towards the front of an OCI …

UOA average duration: 3.5K 7.5K 11.5K

Fe ppm / 1k Miles 3.0 2.3 2.0"


He also shows how the addition of a bypass filter onto a Duramax using synthetic oil did not perform that much better, if at all, to a Duramax using a conventional oil and filter.




He also talks about the Toyota 3.4L gasoline V-6 and here are the numbers regarding iron wear particles at various OCIs.


"UOA Average duration 2.0K 3.5K 7.0K 10K

Fe Ppm / 1K miles 2.6 1.3 1.1 0.9"



Read this article and start the conversation.

 

Not one guy has a thought on the trend of the Fe count going down the further out the oil goes? Don't be shy people. God knows I'm not. I just wanted to get people's thoughts and opinions. There sure is no shortage of either here. Thanks.

 

Data typically says iron wear higher in first 1K miles after an oil change. However, the engines his data are from don't have the fuel dilution issues that stock 6.7s do, so I wouldn't read anything from his data as being applicable to 6.7s after 7K miles because of the fuel dilution we have to deal with.

Also, given the frquency that stock 6.7 owners have to change the oil due to the fuel dilution/EGR issues, seems like dino and synthetic will both be just fine. However, synthetic oil does withstand fuel dilution better than dino.

 

There ya go brother. Thanks for the comment. Brought up a valid point that I did not think of. I wonder what the study of stock 6.7s evaluated the same way would show? Granted, the Duramaxes used for this study were pre emissions. Great point.

 

Dino oil preforms very well without fuel dilution. Even with the first generation of DPF (6.4) and the 6.7.

I have owned both and hard work will reduce fuel dilution.

As far as FE going down the longer the oil run, I don't buy it.

 

How's that?

 

The data shows that it does though, for those specific engines listed. Even with all the abnormal readings and other factors taken into account, that's exactly what it shows. I'm not saying that applies to our 6.7s because there is no study of them. I was just amazed by this trend when I first saw it. But again, I respect your opinion and take on this. Not arguing because not everyone sees things the same.

From the end of this article, the author states that :

Ryan Stark of Blackstone will tell us that the greatest variable that affects wear is usage factor; the data here may well support that conclusion in some circumstances. But what is also clear, at least in all these examples, is that the variation of that usage factor is still “normal” and the standard deviations are large enough that most of us are “normal” in our use of equipment. And OCI durations (too short or long) can also affect wear rates as greatly as usage factors.

Unfortunately, you’ll never know how many abnormalities are present, nor if they have been pre-screened for you, because most UOA services do not perform this extra mathematical filtering. What you can take solace in is the fact that if your UOAs is near, or less than, “universal average” you’re probably in very good shape; you are, in essence, “normal”.

I found these points interesting in the What is applicable to most of us… summation section at the end:


"There is always a “best” combination of equipment, lube and filter, but it goes undiscovered by most people because they do not apply the correct methodology

4) That “best” combination is only applicable to unique individual equipment and given set of limited operational circumstances

5) There is a “sweet spot” where the equipment and lube perform better together

6) That start of that “sweet spot” is unique to each piece of equipment, and lasts much longer than many people would suspect

7) Wear rates will generally shrink as the oil is used, contrary to popular belief

8) Changing oil frequently does not reduce wear in healthy engines with healthy oil

9) Changing oil too soon is a waste of product, regardless of what brand/grade/base stock of lube you choose to utilize"


I changed oil at 7.5k mile OCIs on my 1988 4Runner, 1994 4runner, two 1999 Jeep XJs and a 2009 Escape. I've been running those OCIs for years. If that was too far out, no way would those vehicles have reached the 100ks plus of miles that they put on. I know they are not diesel engines but I bring them up to point out the 7500 mile OCI. Obviously with our 6.7s in stock from, we have to take into consideration fuel dilution caused by the regens but as long as the regens are completing and the truck being driven enough to keep the oil healthy, no reason to change the oil before the truck tells you to. I hear the new 17s+ OLM OCIs are out to 10k + miles. I don't think that Ford would have done that if they hadn't tested that OCI or didn't have confidence in going further out. I understand the whole "oil is cheap but engines/equipment isn't" train of thought, but oil is way more advanced than back in the day. As long as the UOA can confirm the health of engine oil at the longer OCIs, I see no reason to not run it out.

I pasted the points the article made that I thought were pertinent here. Apparently, there is enough data to support the premise of less Fe in ppm as the longer the oil gets runs out. Obviously, I'm not stating to just keep on running the same oil and never change it. I never would have thought this ever if I didn't see it get analyzed for this article.


I recently spoke with the owner and engineer of Renewable Lubricants which is not that far from me inEastern Ohio. I have just recently found this company and it intrigued me how they use a bio based oil for their products. I might try them in the future. Anyways, Bill the owner, likes to use his HDEO in 15w40 grade in all his farm stuff as well as 1999 7.3 Powerstroke. He's way old school because he told me that he changes his oil every 4k miles because "oil is cheap..." The products they make sound like pretty good stuff but I have no experience with them. My point to mentioning this is that even a modern day oil engineer who's older still has old school views when it comes to oil OCIs. IMHO, he's changing the oil ahead of the end of it's useful life.

I recently have found the 6 gallon bags of Motorcraft 10w30 locally at an incredible price. I am going to use the correct dose of LubeGard Bio Tech additive for this upcoming change. I looked into it even further and it is also biobased. I did use it before but it was only one 15 oz bottle. I will use three 15 oz bottles for the correct dosage. I am curious to what the UOA will show after the next Next oil change. We will see and I will post up to show everyone. I also have it their Platinum additive in my trans and transfer case.

 

I have a 96 Isuzu Rodeo with 211,000 miles on it and it has been nothing but a grocery getter all it's life with very little hwy use. It's only seen Dino oil with 3k oil change intervals. Nothing harder on engine oil than short tripping it. I doubt it would have made it as far as it has if the oil was changed at 6-7k intervals.

There certainly is more to consider when choosing OCI than the oil life itself. Crappy air filtration or dusty conditions? better change the oil sooner than later. Additional soot in your diesel engines oil? might want to change it well before the oil life is used up.

I get what your saying "why change the oil before it's useful life is used up" however the only way to know for sure if you are changing the oil at the optimum time is by having UOA done at every oil change because everyone uses their vehicle differently.

 

The 1988 4Runner had about 225k miles when I parked it because the head gasket gave up and I never got around to it. Bought it with almost 150k miles and put on 75k miles. I used just high mileage dino oil. I used the FilterMags on this as well. Never had UOAs done on it or any of the others. Not dusty here and mild off roading for some. Regularly changed the air filters. These were all drivers so no need to change out the oil early as they did not sit. I'm sure if I would have pulled the engine to redo head gasket, look to see how the head was doing, R&R the timing chain as it needed it when I bought it, I would have got at least 75k more miles without UOAs, IMHO which doesn't mean I would have. Not saying I don't believe in them as I do because I am doing them for the F350. And I'm not saying I was changing the oil out at the optimum time either but that's what the factory manual dictated for normal use. The 4Runner only cost me $900 or so. I wasn't too worried about it. Plus those Toyota motors go forever if you maintain them which I did. I did run Redline in the manual trans and transfer case. ,Maybe in the diffs also...

You bring up very valid points about conditions and usage. I guess I was just thinking about me and what my truck is doing now in being a daily driver. Great points though.

 

I agree those toyotas back then were great high milage vehicles. I wanted a 4x4 extended cab Toyota pickup back then but never could afford one.

The Toyota's and the Honda's are what forced the American manufacturers to step up their game to make a more reliable longer lasting vehicle.

 

Lest we forget that vehicle manufacturers are also under heavy pressure to conserve resources too, or at the minimum make it look like they are trying, one way of doing this is extending service intervals and pushing things a lot harder. Was not too long ago it was recommended to change transmission fluid every 50k miles, and even fairly recently change differential fluids every 15k in certain models, under certain use criteria. Now I see a lot more lifetime fill lubricants and only change under severe service. Have the fluids changed? Have the filtration systems changed? I don't think so, but I do think a push for extended service intervals and resource conservation has been taking place. I completely agree with Overkill2 that changing before the end of the oil's useful life is quite wasteful, but it is hard to get most people to subscribe to the ideology that UOA's are necessary, most people today would probably turn their head at you funny and be like what's Fe, TBN, and fuel dilution? Which is why an oil life monitor is crucial for people in today's society. Oil has made leaps and bounds since the days of 3000 mile change intervals. However in certain applications I believe that it still is an adequate interval to run, and oil companies are cheap, they want to make a product that will suffice for engine protection at the lowest cost they can and sell it for the highest cost they can (not true with some, but I believe it is with most big brands) You will find companies out there that are willing to go the extra mile and offer a superior product, such as Lubrication Engineers, and then you have companies like Triax that make claims that seem far too good to be true.

In regards to Fe wear going down the longer a lubricant is used, it is hard to believe, but it has proven to be true in these circumstances, or that sample group, I would like to know on that note, what's the tipping point? how far do you have to run it before it becomes completely detrimental to the engine and wear of the engine. Where is the tipping point, and after you hit that, is it too late?

I am very curious about this kind of stuff, because a company I recently worked for, used to run 3000hr oil change intervals on 3512 CAT diesel engines, crank case capacity was roughly 75-80 gallons, seemed like a fairly long interval but we had a Puradyn 1 micron by-pass filtration system and would change main filters every 1000-1500 hrs. However they switched to no oil changes, until a bad oil sample was observed. By that mind frame, the engine had already began to suffer damage and who knows how long it would be before the lab got back to you. Seemed kind of pointless to me. I'm not the bean counter in charge, but it would have been more logical in my opinion to slowly start increasing intervals until you found that breaking point, maybe a 1000 or 1500 hrs at a time before concluding oil changes as a whole were not necessary. You can buy a lot of oil for the $500k that each engine cost. The same company also bought some oil testing equipment and hired then paid to train a guy to do just oil samples, so they didn't have to pay a 3rd party company to do those anymore. So that brings a whole new level of politics, cause you can bet that guy was under pressure to make sure the oil samples were good to save money.

 

No doubt. Those Honda generators that kick down when there's no power demand are awesome. I'd have no problem driving an old Isuzu or Nissan SUV. Take care of those motors and they'll take care of you. Same with those old Subarus.

The Japs make good stuff, the Chicoms not so much.

 

Great comment there, bobcat. Very well stated and thought out.

I never thought of usage and conditions in my prior statements. As for the lifetime fluid idea, I'm not a subscriber to that at all. I started my OCI mentality with my second truck, the 96 F250. I plowed hard with that truck. That's when I ran into the 30k mile OCI for the trans. I had my system and setup where I would drop the ATF from the return line where I used a bypass valve from Dieselsite.com. I did this every year. Two cases of Dexron/Mercon were cheap at that time IMHO. I replaced the fluid with fresh then did it again. I'd have someone else in the truck shifting through gears and as soon as I saw air, I had them shut it off. I believe I dropped 10 quarts at a pop.
I may do this with the F350 when off warranty unless I start to get UOAs for the trans fluid.

I want to change out the rear diff gear oil before 50k miles and add two of those high temp rare earth magnets that I have in my trans pan. I do believe diff fluids need to be changed because of the metal floating around and the extreme use of the oil in that application. There's a lot of heat there which will break down that oil at one point.

X2 on your comment about most people's reaction to Fe, TBN and fuel dilution.

You make great points about changing the oil to the conditions of the use of the truck. I wouldn't be against extending my OCI in my truck but not now with the warranty intact and probably not with the 10w30 but with a synthetic 10w40 of my choice. I would think 1000 mile intervals with testing beyond when the OLM tells me to change it. But that's for the future. Blackstone usually says let it go another 2k miles. Not saying they are correct but I would try it in smaller increments with testing first.

And x2 on the $500k to buy oil, not one engine instead.