OCI, not when but why?

Chuck FB · June 17

7 minutes ago, diyer2 said:

The less maintenance sales pitch falls right into their plan, we sell parts and vehicles.

Real simple mode of operation, you want to drive it a long time change the fluids more often. Has worked for me over 50 years.

And I was thinking of this factor as well in that if a customer does not well maintain their vehicle ( which means going by the manufactures schedule in most cases ), that vehicle in theory by the time they trade it in or sell it privately will have potentially a shorter life span on some major components as a result and so that vehicles life either cut short or a lot of parts thrown at it to keep it on the road. In either case the manufacturer wins because its either selling more parts or that vehicle has hit the grave yard and becomes a win win for the manufacturers. So indeed the salesmen love a scenario like this .. yes yes, treat that vehicle I sold you like garbage so I will be seeing you sooner then you think for your next new vehicle purchase !

OnTheReel, I looked up my OLM percentage for the last oil change that was done with 2500 miles on it and it read 48% and that was an interval through the winter so more idle time and so on and while not scientific, when I changed the oil it had this weird color to it that I can't say I have seen before and to keep in mind that I burn dyed fuel but so does all other gas vehicles I use and I have to wonder if fuel dilution and allowing more of that dye into the oil was showing up or what but it sure didn't jump out at me as saying I was dropping the oil way too soon. Instead it made me think of what a local long time mechanic had commented on with my truck that he recommended I change the oil every 2500 miles as the number one thing to keep this engine type in good mechanical service. But again its not like that oil was sent to a lab to see where its life was at so this is only anecdotal.

asilverblazer · June 17

4 hours ago, Grumpy Bear said:

Irrational, it doesn't and it can't and it was explained not just by me but by the MANUFACTURE and was disregarded and Stan I find it tiresome. I get it when people are satisfied with there routines. I get it that some don't like having those routines questioned.

Know what I don't get? That these people insist on making sure that no one else gets to explore something they DO find interesting and worth the pursuit.

Guy's if you don't like chocolate ice cream and chocolate ice cream is the topic why the compulsion to pick it up and disrupt the exchange of people that do?

Topic: OCI, not when but why?

Have you considered that just because there is limited documentation on GM's programming of the OLM system that it is not a sign of it's simplicity but a protection of intellectual property? We both agree the system's published parameters are too limited to present an accurate picture of oil quality.

I am not discussing my oil change routines in this comment, I am discussing the parameters of the GM OLM; a key component of "OCI" when and why.

You know what I find interesting? GM trucks, discussing things relevant to those trucks.

If free conversations are not allowed in threads you start I suggest having a discussion with a moderator to have them grant you authority to police and suppress the free exchange of thoughts on your topics accordingly.

Alternatively, if you only want to talk about oil without distractions I suggest bobistheoilguy.com or starting your own blog.

Carry on your discussion of "Engine Wear and ISO 4406"

Grumpy Bear · June 17

3 hours ago, KARNUT said:

So any kind of deviation is not permitted. Even if it manages to touch on Oils Change intervals only if, it addresses your latest thread. Boring.

Stan....YOU'RE bored. Do you hear yourself?

Atlas · June 17

On 6/11/2026 at 10:38 PM, Grumpy Bear said:

ISO 4406 and OCI

Do you know what it is and does it matter?

Coming back to this question, *my* answer is no, it's not something about which I'm knowledgeable. I'd need to read up on it and understand how it applies to we the consumer and our oil change regimens.

One of your bolded points is that fresh oil in a container contains particulate matter. I don't think I'm surprised, maybe a little bit that it seems to be a major factor, but there's manufacturing process involved in oil and it doesn't exactly come in sterile packaging.

How much is filtered out on the first start by an acceptable quality filter (AC Delco, as a baseline) filter?

On the GM OLM discussion, just saying that the "number of engine revolutions" appears to be a factor in oil life... cough... maybe driving style *does* matter.

Grumpy Bear · June 17

3 hours ago, OnTheReel said:

Historically I’ve run about 2 to 1. So two oil changes in the time it takes the OLM to tick over once. I only reset them when the truck starts reminding me to get an oil change and have no use for them.

In no cases has the oil I’ve sampled been fit to run twice as long so the OLM is bunk across GM and other makes/models.

My experience is that there’s ALWAYS something. Either the TBN is ready to fall off the cliff, fuel dilution too high, viscosity down (shear or dilution). But I suppose if you never actually test, you wouldn’t know.

I just spent the last 45K miles doing samples every oil change over more than a full year to get the data for seasons and break-in to broke in.

I found the same thing to be true. Something was always teetering on done or had stepped off the cliff long before the OLM was DOA. In fact, I found about a thousand mile difference between summer and winter. That is during the winter half the OLM was STILL too long. Even the severe schedule was to long in the winter.

Now having done the work I can say I was NOT DISAPOINTED. I saw nothing I didn't already know. Nothing my father hadn't already demonstrated in his 2K OCI's pushing dated iron on dated oils and weak filters to mileages well beyond 300K.

Building on his work through use of Lab testing it wasn't hard to find the correlation between 'sight/feel/odor, the things dad relied on, and test results. Use of current viscosity stable chemistries & filters has pushed that marker for my motors out to 3K summer, 4K winter.

So the early lies were 3K on conventional oil and the lie upon the lie was 7K+. turns out to be off by a factor of two.

So... it is true that modern chemistry has doubled the useful oil life. But the base milage that came from was off by double. It's how good lies work. Partly true, sometimes mostly true so that your :bs: meter isn't set off. It also means that non-shear-stable shelf oils are only now as good as the old oils were in their best case scenario.

So the question now is how do we improve on that? Thus the question into cleanliness among the other items listed in the post quoted below.

If this bores you, feel free not to participate.

On 6/16/2026 at 6:00 AM, Grumpy Bear said:

Engine Wear and ISO 4406

1.) Cold Starts.

2.) High Particle Count.

3.) Low operating temperature viscosity and high low temperature cranking viscosity.

4.) Depleted AW, Friction and Acid packages.

5.) High engine load.

https://me.caltexlubricants.com/en_me/home/learning/from-chevron/heavy-duty-diesel-vehicles-and-equipment/The-Importance-of-Clean-Engine-Oil-and-Its-Impact-on-Equipment-and-Business-Performance.html

High particle counts have five sources.

1.) They are manufactured within the engine. Both wear debris and amalgamation of degradation products and combustion driven soot (worse in GDI).

2.) They are ingested via intake air. Ever hear the best oil filter is a good air filter?

3.) They are entrained in the fuel.

4.) This one is insidious. They are introduced in 'fresh oil'.

5.) They are introduced during the oil change.

ISO 4406 is the test that measures and quantifies the combine effects of all of the above particle related issues. You can mitigate your way into multiples of engine life by being attentive to them all.

https://www.hyprofiltration.com/blog/is-new-oil-clean

(from the link above)

[Quote] What Is the Recommended ISO 4406 Cleanliness Code for New Oil?

A good upper limit for new oil cleanliness is 16/14/11 (ISO 4406). Typical new oil usually has ISO codes of 19/17/15 or worse, which is far too dirty for sensitive components. This can be a major cause of degradation and premature failure. [Close quote].

Source of graph: Machinery Lubrication (GM Study)

Grumpy Bear · June 17

29 minutes ago, Atlas said:

Coming back to this question, *my* answer is no, it's not something about which I'm knowledgeable. I'd need to read up on it and understand how it applies to we the consumer and our oil change regimens.

One of your bolded points is that fresh oil in a container contains particulate matter. I don't think I'm surprised, maybe a little bit that it seems to be a major factor, but there's manufacturing process involved in oil and it doesn't exactly come in sterile packaging.

How much is filtered out on the first start by an acceptable quality filter (AC Delco, as a baseline) filter?

On the GM OLM discussion, just saying that the "number of engine revolutions" appears to be a factor in oil life... cough... maybe driving style *does* matter.

Thank you for keeping the train on the tracks and for a thoughtful engagement. I enjoyed the reflection on a previous stance to refine and improve your position. I like that inquisitive flexibility about you Atlas.

No the process isn't sterile. Hundreds, perhaps thousands of miles of piping, vessels, pumps. Chevron, the people I worked for, were keenly aware that there is a market for what is known as their "ISOCLEAN" line of lubricants. These are lubricants that are the same as those sold bulk that are further processed by filtration to a level your particular application demands. They will filter and package and provide lab documentation as required. Do not kid yourself. Every gallon of oil that goes into a Chevron Turbine, reciprocating compressor, generator is prefiltered and tested before being charged. Lest wise it was when I was there in the plants I worked in.

There are requirements set by manufactures for the cleanliness of the oils used in their equipment. OTR such as CUMMINS has standards shared with customers on this. Commercial interest selling to Ma and Pa do, but don't share that information. Not even upon request but internally, they do exist.

The GM study sited, (Graph from Machinery Lubrication in previous post) only shows "relative" importance. I find that fascinating. By constructing the graph like this they admit there are dozens of factors in engine life and via scientific method determined the effect of 'relative cleanliness' on engine life not in miles but in 'FACTORS'. This allows a certain amount of reverse engineering does it not? They even provided some touchstones. Beta 75 as a reference point. Wonderful stuff!!

Smaller blenders CAN and some DO take the time and effort to do better than a refinery or large bulk blender, like Warren Oil, in improving the "in the can" cleanliness. No I don't have a list but testing could generate that information.

Again, but one of several levers we can pull to improve engine life. The simplest is keeping a clean work station while doing your own oil changes.

Edited June 17 by Grumpy Bear

asilverblazer · June 17

17 hours ago, Grumpy Bear said:

18-NA-125 is the document from the OEM, GM, and yet; and although they give a full and detailed discussion of the inputs and outputs your conclusion is ?

Am I reading that right? They gave you the answer and your response is , I'm trusting it anyway?

Have you ever heard me say, "I don't do irrational"?

I apologize, I missed this post, at risk of going off CURRENT TOPIC.

I'm not saying it is BS, I'm questioning how much information is being held back. GM is NOT going to spell out exactly every parameter in the algorithm. Liability, intellectual property, etc.

I'm not naive enough to believe that it is as simple as revolutions, coolant temperature, miles, time; are you?

I don't do irrational either, and boiling the OLM down to four simple values that I could code in an afternoon (I'm not a coder) is irrational - unless it suits your agenda to ignore it.

Atlas · June 17

On the subject of OLM, Gm's OLM tool may be more "informed" than others brands. I recall OLM's in mid-2000's Chrysler products literally counting down a set number of miles. That's all the OLM appeared to be.

I would actually expect GM to be able to explain the parameters that their OLM takes into account from a high level. No, I would not expect them to disclose their software coding or data analysis around their parameters.

So we're talking about two different topics, so to continue the subject on the other one, I'd be curious to know how much "standard particulate matter" in fresh oil is able to be filtered at first start by a fresh oil filter. How much particulate matter is enough to "matter"?

I.e. how much of a "lever" do we think this equates to (variability in particulate content, in fresh oils, between different makes/brands, some which filter less, and some that filter more).

We can say that more particles = more wear = shorter engine life as a logical statement and use that data with a little marketing to scare people into selecting a more refined/filtered oil. Using a similie, is this like deciding to forego two alcoholic drinks in a lifetime because we're worried about the potential impact on lifespan? Are there numbers which translate the ISO test results into a quantifiable increase in wear for a given engine/use case?

Edited June 17 by Atlas

Chuck FB · June 18

The not as clean as one would assume theme with the new engine oil, that reminds me of comments over the years with mechanics not always being so on board with filling an oil filter, not from the center anyway due to that typically being the clean side of the filter, danger of some contaminant falling into the filter if not careful but the realization now that the oil may not be as pure as one had assumed it would surely be. Yes it would be possible to fill from the small holes but that means messing with something to prop open the anti drain back valve if the filter is so equipped and not damage that valve in the process. Me, I have hardly ever prefilled an engine oil filter however I have prefilled diesel fuel filters with a filter on a fuel bulk tank and for anyone that has messed with diesel engines with filters and units that have a limited or no way of priming them, putting on a dry filter is a bad day to say the least with those crappy systems. But anyway back to not so clean engine oil, indeed perhaps its not so bad after all that I have not made a practice of prefilling oil filters.

As Grumpy Bear commented on keeping things clean, that I really have to wonder what the typical practice is at a dealer or any other shop that changes engine oil, do they make sure to wipe or wash off the oil plug and certainly if it fell into some gunk or onto a dirty floor, or that they wiped the filter mounting flange and didn't go and use some dirty rag and end up adding dirt to the inside of the head of the filter mount. Or be careless in how they stored or handled the new filter and if they were bumping into items under the vehicle with the filter opening facing up and having dirt drop right into the filter and if so right into the threaded center that is on the clean side. The top side, did they clean away the built up gunk that may be around the filler before removing the cap or to be really careful at that point that something right close to the filler hole that was hidden under the caps flange won't fall into the engine. Or did they clean the funnel or was that just laying there covered in oil from the oil change before and dust kicked up from sweeping the floor stuck to the oil and now that will go running into the next persons engine due to just not cleaning the funnel as "they won't know anyway" attitude as that young guy is more worried about taking a break so he can go outside and smoke a joint. Just random points that came to mind when I think about what some hired personnel may do that the shop foreman has no idea of or perhaps the whole attitude of some shops may be "eh ... who cares, they will never know the difference anyway".

Grumpy Bear · June 18

7 hours ago, Atlas said:

i.e. how much of a "lever" do we think this equates to (variability in particulate content, in fresh oils, between different makes/brands, some which filter less, and some that filter more).

We can say that more particles = more wear = shorter engine life as a logical statement and use that data with a little marketing to scare people into selecting a more refined/filtered oil. Using a similie, is this like deciding to forego two alcoholic drinks in a lifetime because we're worried about the potential impact on lifespan? Are there numbers which translate the ISO test results into a quantifiable increase in wear for a given engine/use case?

Here's a starter kit:

CC Jensen, a Danish oil testing Concern gives us the following guidelines:

ISO 14/12/10 Very Clean Oil

ISO 16/14/11 Clean Oil

ISO 17/15/12 Lightly Contaminated

ISO 19/17/14 New Oil

ISO 22/20/17 Very Contaminated and not suitable for any service.

In addition CC Jensen gives a table showing how engine life is increased by cleaning up the oil. For example cleaning the oil from 19/17/14 to 13/11/8 will extend motor life by a factor of 6X.

But even cleaning it two “Life Extension Classes” will double motor life. So perhaps giving those classes would be useful:

21/19/16

20/18/15

19/17/14

18/16/13

17/15/12

16/14/11

15/13/10

14/12/9

13/11/8

*************************************

https://testoil.com/program-management/setting-iso-cleanliness-targets/

Third paragraph from the bottom will give a starting point.

Your next question should be, okay 10um at what Beta ratio and the answer is in the graph Beta 75.

Then the next question is what is your chosen filters profile? (Purolator PL series below) The red dot is Beta 75. This was the information I obtained from MANN a few years ago. So the best filters, Purolator One, AMSOIL EA, FRAM Ultra, Royal Purple, Bosch Premium should get a doubling engine life over filters like Purolator L, any service filter from any quick lube, WIX, NAPA, STP, Mobil 1, Purolator BOSS.

And as noted by CC Jensen a 2-5 micron @ Beta 200 bypass system has the capability of a six fold improvement. AMSOIL has such a system as does Donaldson.

Now having said all that testing is the touchstone. Test the oil NEW and test it with your chosen filter. Then test over milage. Do the work, get the result. But understand this in NOT absolute BECAUSE this is one factor in isolation.

Example:

A valve spring supplier can state that with cam X and a valve train of Y grams the valves will not float to 7K rpm. is that true if the builder choose a system 20 grams over limit? Common sense must be used and limits understood.

Grumpy Bear · Thursday at 01:21 PM

Practical Application ISO 4406

I think this oil cleanliness thing is going to boil down to ones personal resolve. The information is there but applying it I believe will test your commitment to the machine. Implementation would involve building or buying a prefilter or purchase of an "ISOCLEAN" oil. Then installing a single digit micron bypass system. A good deal of testing and about 99.9% of you are saying at that point....yea.....not my cuppa tea. So what can you do?

You already did the first step. Get educated and leave the bias at the door. Be aware of the its, cleanliness, importance.

Do your own work if you can. Keep the equipment clean. Not just your funnel but the engine bay. Use sealed containers. Think it through.

I believe you will find, as I did, that the tightest absolute full flow filters (Beta 200) will be around 20 micron. That will yield on average a Beta 75 of 10-15 micron. They are few in number by brand and price point. Loose filters are a dime a dozen and even the best brands have lines of loose filters. Some cleverly marketed as "Extended Service". Others will market flow over efficiency. But I think the take away once informed is that the extra cost of the best offered is a bargain. There are cheaper filters with good efficiency that are equal in performance to niche brands with big prices. Your Quick Lube is about a 40 micron unit. This is where your dealer is a plus. the AC-Delco filter is a good step up from those places. Even better if you specify the UPF line.

Be skeptical of marketing. Buying an oil that is made from GTL advertised as the cleanest base oil is using a truth to support a lie. While GTL's are made from debris free gas the processing equipment and post handling is just like any other oil. It also ignores the fact that PAO's and Esters are also gas in origin. Any private prescreening testing you would do, and some have done, would yield a result only good for the batch you tested. AMSOIL and Schaeffer's have built a reputation for paying attention to this detail.

Context. Cold starts account for at least 75%, or more, of an engines wear. But of the remaining 25% ish, over 80% is caused by particle count. Now where do we find high milage motors that use this type of information efficiently? OTR trucking!

Now, anyone want to build a prefilter or off line cleaning system anyway?

Atlas · Friday at 02:23 PM

@Grumpy Bear the conclusion from your post about doubling engine life has me curious. Are we literally talking an expected life of 250,000 miles potentially becomes 500,000 miles with a step up in filtration for fresh oil at "the oil factory" when it's bottled? I know you said that's a single variable among many, but, that's significant if the implication extends that far into a real world use case. I would think the oil marketing folks would really eat that up and make it known.

Particles introduced during oil change is a fairly easy one to avoid, but probably not intuitive as one would think. I.e. using a clean funnel. But...what was it wiped with? Paper towel leaves behind little fibers. A solvent if not dried is not something one would want to introduce into their engine with clean oil. And, keeping the oil filler neck clean and free of buildup.. Look at some guys engine bays and they're an absolute mess. Some say that's better than the drawbacks of cleaning it. I'm not a buyer of that idea.

I've also wondered if "flooding" the top end of the engine with oil while filling is a bad idea. During normal lubrication the oil flows in a gutter back into the galleys. But if you flood the area you're potentially washing the top of the rockers, springs, and other areas which may not get much oil wash normally, and you're mixing all that into the new oil. I just don't have the patience to pour slowly.

Chuck FB · Friday at 03:19 PM

A while back on another thread there were comments and thoughts on air filters and I know that can tend to be a bit of a hot topic because of outfits that have a vested interest in selling aftermarket air boxes fitted with the gauze type of oiled elements touting the lower air restriction. However and unfortunately I don't know where I have seen the test results in the past about the amount of dirt through a test procedure that these style of filters do pass more dirt through than a properly designed ( not some cheap Chinese knock off ) paper/synesthetic media filter can do. Lake Speed had a conversation on that topic with one of the employees at Donaldson and there seemed to be a consensus of these oiled filters falling short in the absolute percentage of dirt holdback.

Which all ties back into how good the air filter is on the engine at keeping dirt out as that is going to reflect as a contaminant introduced into the oil as well as cylinder wear even if some of that dirt does find its way out of the exhaust rather then the crank case. Put another way that one can throw the kitchen sink at filtering the oil and using a bypass system which I fully expect will do nothing but good for the oils contamination but if the air filter system isn't doing its job then its preventing the engine from reaching the best wear/lasting case scenario instead.

Now perhaps this topic is or isn't for this particular thread but Grumpy Bear or anyone else for that matter, do you have access to some scientific trust worthy testing on engine air filter types to get some proper comparison data to post up.

Chuck FB · Friday at 03:26 PM

58 minutes ago, Atlas said:

@Grumpy Bear the conclusion from your post about doubling engine life has me curious. Are we literally talking an expected life of 250,000 miles potentially becomes 500,000 miles with a step up in filtration for fresh oil at "the oil factory" when it's bottled? I know you said that's a single variable among many, but, that's significant if the implication extends that far into a real world use case. I would think the oil marketing folks would really eat that up and make it known.

Particles introduced during oil change is a fairly easy one to avoid, but probably not intuitive as one would think. I.e. using a clean funnel. But...what was it wiped with? Paper towel leaves behind little fibers. A solvent if not dried is not something one would want to introduce into their engine with clean oil. And, keeping the oil filler neck clean and free of buildup.. Look at some guys engine bays and they're an absolute mess. Some say that's better than the drawbacks of cleaning it. I'm not a buyer of that idea.

I've also wondered if "flooding" the top end of the engine with oil while filling is a bad idea. During normal lubrication the oil flows in a gutter back into the galleys. But if you flood the area you're potentially washing the top of the rockers, springs, and other areas which may not get much oil wash normally, and you're mixing all that into the new oil. I just don't have the patience to pour slowly.

If all oil manufacturers had to meet a higher standard for not just the initial filtering of the oil but that they had to improve on their formulation so that the oil cleaned the engine such as the Valvoline R&P or the new Mobil product ( assuming it works similar of course ), and the oil was changed on an interval based on good UOA data, there shouldn't be any gremlins running around like miniture rats on top of your heads to be washed down into the oil pan below

Grumpy Bear · Friday at 10:14 PM

7 hours ago, Atlas said:

@Grumpy Bear the conclusion from your post about doubling engine life has me curious. Are we literally talking an expected life of 250,000 miles potentially becomes 500,000 miles with a step up in filtration for fresh oil at "the oil factory" when it's bottled? I know you said that's a single variable among many, but, that's significant if the implication extends that far into a real world use case. I would think the oil marketing folks would really eat that up and make it known.

Particles introduced during oil change is a fairly easy one to avoid, but probably not intuitive as one would think. I.e. using a clean funnel. But...what was it wiped with? Paper towel leaves behind little fibers. A solvent if not dried is not something one would want to introduce into their engine with clean oil. And, keeping the oil filler neck clean and free of buildup.. Look at some guys engine bays and they're an absolute mess. Some say that's better than the drawbacks of cleaning it. I'm not a buyer of that idea.

I've also wondered if "flooding" the top end of the engine with oil while filling is a bad idea. During normal lubrication the oil flows in a gutter back into the galleys. But if you flood the area you're potentially washing the top of the rockers, springs, and other areas which may not get much oil wash normally, and you're mixing all that into the new oil. I just don't have the patience to pour slowly.

Interesting question which you partly answered in the word 'potentially'. I think that is going to be a 'point of reference' inquiry. What are the touchstones?

This will sound petty but it is the main source of end fighting in threads on this topic. Define a motors "Life". Think about the various arguments that have been entertained on these pages in that very argument.

I can only speak from my viewpoint. Engine "Life" in my world is defined by power cylinder integrity. For the majority of engines it is the bore/ring interface that quits first. Loss of seal. Oil consumption and loss of power. Most Pro motor builders would agree and there is a good deal of information on using "Leak Down" as a primary indicator of bore integrity. At home a compression test is more the thing. If we can agree on that then I think CC Jensen has done its homework and I'd find it valid.

Now by my own definition, Dizzy, wife's Ecotec 2.4 I-4 has been dead since about 80K miles. And yet we have logged over 200K miles more on it. "Life" and "Usefulness" are therefore independent.

I know a mature fella right now who has just hit 300K on a Mitsubishi 3A92 NA MPFI motor and has done compression test every 100K. It was 205 psi after break in and is now about 195 and still even. He uses shelf oil but good filters and adheres to a 3K mile OCI. He even do UOA's on each of them for the first 50K.

I also know a fleet mechanic with that same motor that gets 300 to 500 K out of them but the are oil using, wristpin sloppy, skirt slapping motors. He ran one with a piston pin so loose the piston was bouncing off the cylinder head for about 20K miles before he called TOD. Both of them claim success. :crackup: