Oil Life Monitors

[UncleDave]

Originally Posted by oil_film_movies
Originally Posted by UncleDave
Has GM disclosed how their system even works like Honda has? Seems most guys keep this all a secret whereas Honda is open about how they developed their algorithm.
UD
The Honda paper cited above I've not seen before, nice summary. It looks like GM's algorithm, probably barely sidestepping GM patents !!
From https://etda.libraries.psu.edu/files/final_submissions/392 we have the basic flowchart for GM. In the last few years, probably due to direct injection engine's carbon soot problems (timing chains, etc.), GM now uses their old algorithm, but cuts it off at 7,500 miles or 1 year max.




Fairly similar

Thanks for the paste up, I'd seen this prior and noticed there is scarce to no background behind some stages (like 214) where Honda is pretty forthcoming with how they get to specific numbers.

I wonder what the average GM OLM OCI is vs theoretical max?

It seems Honda gets by without an oil temp sensor (at least there is no gauge) and completely infers that data. Maybe GM does as well?

There is a fairly large gap of 25% between max possible miles between the 2 systems - Both DI "soot makers"

Im guessing this diff is mainly a function of the Hondas belt, vs GMs timing chain which contributes to shear and if you are starting at 0W-20 you don't have a lot of viscosity to lose.

UD

 

[Whimsey]

As I've said before, the iOLM in our 2017 2.3 EB Explorer has been following with 1% loss of oil life per 1,000 miles of use. So to get to 0, which Ford says is fine, is 10,000 miles. I've never let the iOLM get down to 0. I try to change it at ~6,500-7,500 miles and the iOLM is reading 35%-25% oil life left. It doesn't matter how it's driven or the seasonal conditions, it's still 1% loss per 1,000 miles driven. Ford seems to be optimistic about their fluid lifes. Such as the transmission ATF for 150,000 miles on the factory fill and "lifetime" on the AWD/4X4 PTU unit factory fill of 75W-140. The transmission will most likely make it to the end of the warranty, then it's your problem if you hold onto the vehicle for a long time. If the PTU makes it to the end of the warranty then Ford got lucky. You however didn't because the odds are it'll fail not long after the warranty expires due to the fluid being trashed due to heat and lack of fluid capacity.

Whimsey

 

[oil_film_movies]

Originally Posted by UncleDave
I wonder what the average GM OLM OCI is vs theoretical max?
My '18 Equinox pegs to the 7,500 mile maximum every time. I would have to be driving like a madman or idling a lot or taking nothing but short trips to get an earlier miles OCI.

Originally Posted by UncleDave
It seems Honda gets by without an oil temp sensor (at least there is no gauge) and completely infers that data. Maybe GM does as well?
The GM can use either. Maybe Corvette has direct oil temperature, but most probably get an estimated calculated oil temperature.

Originally Posted by UncleDave
Thanks for the paste up, I'd seen this prior and noticed there is scarce to no background behind some stages (like 214) where Honda is pretty forthcoming with how they get to specific numbers.
The "214" is contaminant penalty, and is a linear function as on page 12 and 13:

 

[UncleDave]

I couldn't figure out what you meant by page 12 and 13 - the link wasn't a diff color so I didnt click it or even notice it was a hyperlink at all.

Gonna absorb this - and Ive been looking for this piece since reading it the first time - thanks sir

UD

 

[UncleDave]

Originally Posted by Whimsey
As I've said before, the iOLM in our 2017 2.3 EB Explorer has been following with 1% loss of oil life per 1,000 miles of use. So to get to 0, which Ford says is fine, is 10,000 miles. I've never let the iOLM get down to 0. I try to change it at ~6,500-7,500 miles and the iOLM is reading 35%-25% oil life left. It doesn't matter how it's driven or the seasonal conditions, it's still 1% loss per 1,000 miles driven. Ford seems to be optimistic about their fluid lifes. Such as the transmission ATF for 150,000 miles on the factory fill and "lifetime" on the AWD/4X4 PTU unit factory fill of 75W-140. The transmission will most likely make it to the end of the warranty, then it's your problem if you hold onto the vehicle for a long time. If the PTU makes it to the end of the warranty then Ford got lucky. You however didn't because the odds are it'll fail not long after the warranty expires due to the fluid being trashed due to heat and lack of fluid capacity.

Whimsey


I've read similar elsewhere - based on its behavior it seems Ford has a dumb count down system

The data supplied by OFM suggest its a complex algorithm that uses implied oil temp similar to what we've seen from Honda and GM.


UD

 

[oil_film_movies]

Ford's "iOLM" on my '15 Ford C-Max also appears to count miles to 10,000 miles. Still, they could be using some algorithm, which always displays the lesser of the dumb miles countdown, the dumb time countdown, and the sophisticated internal algorithm. It actually figures up all three ways, and displays the smallest percentage. .....That way, it kinda looks like its just counting down time or miles.

My '18 GM Chevy Equinox does that. It figures straight dumb 7,500 miles %, then it calculates the time value to 1 year, and finally it calculates its usual complicated algorithm. All WE SEE is the least of all three.

 

[Hall]

Originally Posted by UncleDave
I've read similar elsewhere - based on its behavior it seems Ford has a dumb count down system
It could be or it could be that what Ford considers "normal" service is very different than what many drivers think is normal vs severe. To the contrary of what you've heard, some drivers see the monitor calculate oil life other than 10% per 1000 miles (more like 10% per 500-750). In those cases, they clearly use their vehicles a bit "harder" and the system adjusts for them.

Again, odds are that 90% of drivers, even soccer moms or dads that do frequent stop-and-go trips to sports, grocery, doctor appointments, etc still don't fall under severe service.

 

[Hall]

Originally Posted by Whimsey
I try to change it at ~6,500-7,500 miles and the iOLM is reading 35%-25% oil life left.

If you wanted, instead of resetting the monitor to 100% starting point, you can have it start at different values, i.e. 50%, 75%, etc.

 

[oil_film_movies]

Here is why OLM's usually beat a person's guess about when to change oil:

https://www.machinerylubrication.com/Read/77/gm's-oil-life-system-improves-timing-of-oil-change for an explanation of terms in their graph.
Notice things can go south rather quickly near the end. It is when the additives run out.

 

[SteveSRT8]

GM's V8 calibrations are nearly perfect. They had issues with other engines. We have run 6.0's to 500k miles using only the OLM and whatever synth was on sale at WM.

Our trucks used in stationary operations run almost exactly 4500 miles, our Silverados used for deliveries can go 10-12k miles depending on highway versus city work. And yes, if you watch carefully you can see the rate of degradation accelerate towards the end of the life calculations.

GM's OLM has saved us a ton of money....

 

[BlueOvalFitter]

My recommendation for ANY OLM is a piece of black tape over it.

 

[ka9mnx]

If I had one I would use it...

 

[WobblyElvis]

I could keep a pad of paper and pen in my car and every time I drive it I could write down the miles driven and the relative conditions under which it was driven. Things like short trips or cold starts. Or I could let the OLM do this for me. Conversely, the oil could be changed every 3,000 miles to 10,000 miles or any random number I pick. If I were to pick every 5,000 miles, sometimes I would be wasting oil/time and other times I may go past the useful life of the oil. Seems like a no brainer to me to use the OLM.

Should, due to UOA I believe the OLM over uses the oil, I can change oil when the monitor counts down to %20 or whatever number I see fit. I like having an OLM.

 

[4WD]

Originally Posted by SteveSRT8
GM's V8 calibrations are nearly perfect. They had issues with other engines. We have run 6.0's to 500k miles using only the OLM and whatever synth was on sale at WM.

Our trucks used in stationary operations run almost exactly 4500 miles, our Silverados used for deliveries can go 10-12k miles depending on highway versus city work. And yes, if you watch carefully you can see the rate of degradation accelerate towards the end of the life calculations.

GM's OLM has saved us a ton of money....


Great example of the OLM's potential. I have an even enough pattern that once the OLM defines an upper limit … I will use that and my schedule to pick a time. If I'll be out of town and I forecast the wife's SUV to be low percentage while away … still cheaper for me to change early and DIY is the only shingle I trust …

 

[Baveux]

Follow the OLM a few times, take a few samples, and see like me that your oil will come back with the mention ... serviceable ...... so for me no more oil and money wasted . The OLM was right 3 x on my 2014 Ford F150 3.5 eco.

 

[Triple_Se7en]

Serviceable does not tell you that the buildup inside your engine is getting worse....... at least not until serviceable turns into a breakdown, somewhere down the line.
Respect, appreciate and properly maintain vehicle engines. Serviceable only means things are still functioning currently.

Oil and filter are both dirt cheap, in comparison to repair costs of the engine. But disregard everything I just said, if you sell the vehicle prematurely to the average life of your vehicle, accidents, fire .....etc.... excluding.

 

[Malo83]

Originally Posted by BlueOvalFitter
My recommendation for ANY OLM is a piece of black tape over it.

 

[Baveux]

Originally Posted by Triple_Se7en
Serviceable does not tell you that the buildup inside your engine is getting worse....... at least not until serviceable turns into a breakdown, somewhere down the line.
Respect, appreciate and properly maintain vehicle engines. Serviceable only means things are still functioning currently.

Oil and filter are both dirt cheap, in comparison to repair costs of the engine. But disregard everything I just said, if you sell the vehicle prematurely to the average life of your vehicle, accidents, fire .....etc.... excluding.


I understand that filters and oil are cheap but why are we so inclined to dispose of something that is still servicing you well ?


We cannot predict a catastrophy however if an oil analysis report that the oil is still serviceable on what base am I going to argue with that .

If one use quality and that the oil is good, TBN Tan Ok , no fuel dilution out of range , silicone within spec etc etc why dumping it ? Good quality oil should be able to keep your engine clean isnt it ? And if your engine is dirty that should be seen in the oil analysis no ? I dont know Im asking

Fresh oil in this case isnt going to serve me better, just longer I would say

if we cant go by several oil analysis then lets go back to 3000 miles oil change and be done with it

 

[tiger862]

My Saturn had OLM that never went off after a year so I reset it and never seen message. Most was 6k in a year. I bought Caravan with 3k on it and manual states severe driving conditions which I fall under it is 4k with normal driving to follow OLM, 1year or 10k. I changed at 4500 with Synthetic Blend then made switch to Synthetic which I will go 1 year or OLM just as I did with last vehicle. I feel a good synthetic will go 10k so I just run a name brand that is made for severe driving.

 

[pitzel]

Important to adhere to the OLM and not change the oil more frequently than spec'ed by the OLM. DI engines are very sensitive to overly frequent changing of oil.