A Look at GM's Oil Life Monitoring System

[f5journal]

On a related note, I just got an advisory from GM to bring my 2009 V6 Traverse in to "recalibrate the Engine Oil Life Monitor" Seems like they are having pre-mature timing chain wear and they need at least a band-aid fix for it so that you might make it past the warrantee period

[CamaroSpike23]

Originally Posted by el ess X

OnStar is "on my butt" about the Camaro OLM reading like in the 80s yet it's been a bit over a year since an oil change.



Hence the little warning sign on my OnStar report. They suspect I'm not resetting my OLM, but fugg 'em. Car only has 6800 miles on it. So when I change my oil, THEN I'll reset it.

I've used the OLM to schedule oil changes for all the vehicles so equipped and never had an issue with any of them. None. I believe...

doesnt the manual say to change it at least every year or when the OLM says to?

Originally Posted by camaro1

the system doesnt know what you put in for oil,, the system does not do any tests on the oil,, it is just a calculated value based on rpm, speed, load, time, temperature

you could put drain oil back in your car, reset the OLM to 100% and the computer will start its calculation again, same as any other oil used

the system doesnt need to know whether you've put synthetic or dino oil in the car.

you could pour your stuff back in and reset it, but the OLM will pop up sooner due to the lack of ZDDP and other constituents in the oil. the deterioration factor will increase due to the oils protective wear properties already being "used up"

I've done this same "experiment" on a 2008 Silverado. drained the oil out, poured it back in with a new filter and reset the OLM and it wasnt but even 2k miles before the OLM was reading down to 40%

[IamJacksCamaro]

Great information, thanks for posting. I am going to start checking my OLM.

[Ironheadspearo]

The key is not so much as miles on the oil it is the kind of miles you have on the oil.....
were the miles Highway?
were the miles City?
were the miles driving 90 mph?
were the miles driving 70 mph?
were the miles drag racing light to light?

you have to use common sense with this. also it is normal for cars to use oil, just because you have no leaks doesnt mean the car will remain at full leevel for 5000 miles. you might be suprized to know that your camaro is most likely going to use 1 quart of oil per 5000 miles depending on how you drive it. higher RPM's = more consumption of oil.

if you do your own oil changes you should get a good feel for what kind of mileage intervals you should be using. it is trial and error with each vehicle IMO. it all depends on how your driving that thing.

I used to race motocross and we changed the oil for each track day.... because the bike was held wide open for 20 minute sessions a few times. now if i were just leisurely riding the same bike it would be a waste to change that oil every time i took the bike out.

[camaro1]

Originally Posted by CamaroSpike23

doesnt the manual say to change it at least every year or when the OLM says to?



the system doesnt need to know whether you've put synthetic or dino oil in the car.

you could pour your stuff back in and reset it, but the OLM will pop up sooner due to the lack of ZDDP and other constituents in the oil. the deterioration factor will increase due to the oils protective wear properties already being "used up"

I've done this same "experiment" on a 2008 Silverado. drained the oil out, poured it back in with a new filter and reset the OLM and it wasnt but even 2k miles before the OLM was reading down to 40% :thumbsup:

this info is wrong,, the gm system does not have an oil quality sensor, it is just a calculated number based off of load, rpm, mph, temp,, it does not check the oil itself in any way. the only oil sensors gm has are oil level and oil pressure,, The system itself uses an algorithm that tracks engine revolutions and temperature and predicts oil life based on these parameters and driver use.



some european vehicles do have an oil quality sensor but non of the US vehicles do.

[CamaroSpike23]

Originally Posted by camaro1

this info is wrong,, the gm system does not have an oil quality sensor, it is just a calculated number based off of load, rpm, mph, temp,, it does not check the oil itself in any way. the only oil sensors gm has are oil level and oil pressure,, The system itself uses an algorithm that tracks engine revolutions and temperature and predicts oil life based on these parameters and driver use.



some european vehicles do have an oil quality sensor but non of the US vehicles do.

What I'm saying is that as the protective properties of the oil break down, higher temps and worse flow characteristics are just some of the results, the OLM sees this and adjusts your % based off of the algorithm and the parameters it can see.

I wont say its completely fool proof, but I wont just blindly state that "it just doesnt work" either

[JSC81]

Originally Posted by camaro1

this info is wrong,, the gm system does not have an oil quality sensor, it is just a calculated number based off of load, rpm, mph, temp,, it does not check the oil itself in any way. the only oil sensors gm has are oil level and oil pressure,, The system itself uses an algorithm that tracks engine revolutions and temperature and predicts oil life based on these parameters and driver use.



some european vehicles do have an oil quality sensor but non of the US vehicles do.

Why wouldnt you consider it an oil quality sensor? The sensor from what I read is based of you would think the recomended oil for the car and when it should break down based on all the data it has collected. In my eyes if you use the correct oil for the car IT IS an oil quality sensor. It just does it another way.

[1BADLS3]

Originally Posted by JSC81

Why wouldnt you consider it an oil quality sensor? The sensor from what I read is based of you would think the recomended oil for the car and when it should break down based on all the data it has collected. In my eyes if you use the correct oil for the car IT IS an oil quality sensor. It just does it another way.

It's not a physical sensor that hangs out in the crankcase checking the oil as it moves throughout the engine. It's software with calculations that, in theory, predict the quality of the oil as it is inside the engine. Make sense? Call it an "oil quality forecasting tool".

[camaro1]

Originally Posted by 1BADLS3

It's not a physical sensor that hangs out in the crankcase checking the oil as it moves throughout the engine. It's software with calculations that, in theory, predict the quality of the oil as it is inside the engine. Make sense? Call it an "oil quality forecasting tool".

correct,, there is no sensor that is in contact with the oil to actually tell you if the oil is good or bad,, its just a calculation. so you can put whatever oil in you want and the system doesnt know the differance and will calculate the oil life the same no matter what oil is in the vehicle, or what quality oil

some european cars do have the oil quality technology and can actually measure the oils quality from a special sensor in the oil pan.

[Russell James]

The system does use sensors.... crank sensor and coolant temp sensor.

[NavyDood]

Originally Posted by Russell James

I never bought into the OLM theory, 3 -5 K changes for me. I've done a ton of oil changes on other peoples cars where they take it down to 0% on the OLM, and that oil looks nasty. I'll trust my eyes before theories, and now there is a recall to back up that suspicion that real long oil change intervals may not be so great - gee who'd of thunk it.

You better have those eyes of yours patented and sell your expertise for millions then. You are sitting on a gold mine and don't even know it.

Originally Posted by fielderLS3

I'd never use the oil life monitor. I go by how it looks on the stick. I know using the oil monitor is "probably" ok, but "probably" doesn't cut it when it comes to an engine on a $35,000 car.

Same goes for your eyes.

Originally Posted by f5journal

On a related note, I just got an advisory from GM to bring my 2009 V6 Traverse in to "recalibrate the Engine Oil Life Monitor" Seems like they are having pre-mature timing chain wear and they need at least a band-aid fix for it so that you might make it past the warrantee period

Totally agree. Sounds like they are using inferior parts.

Originally Posted by CamaroSpike23

What I'm saying is that as the protective properties of the oil break down, higher temps and worse flow characteristics are just some of the results, the OLM sees this and adjusts your % based off of the algorithm and the parameters it can see.

OLM can't read the breakdown or the flow characteristics. Temps it monitors.

As much as you all want to justify that the system is faulted, today's oils are greatly advanced even in comparison to the 4th Gen days. Even though Mobil1 is a Group III dino based synthetic, it's additives are what give it its awesome track record. IMO there isn't a better Group III on the market than Mobil1.

I have said this before on here, your eyes and your fingers will never be able to tell you what the true condition of your oil is. Only an analysis can. For those of you that change your oil at 3000 or 5000 miles (for that feel good feeling), if you were to do an analysis on it im willing to bet that it could easily go twice as long if not triple.

[spurscar]

tl;dr

So he's saying something about 10% being okay to get down to before changing it?

[Russell James]

When your looking at a used car, would you rather buy one from someone who changes the oil religiously every 3K. Or one that goes to 0%?

Experienced eyes can tell a lot by looking at the dipstick. What's one of the first thing a sharp used car buyer does? Pop the hood, pull the dipstick. Nice and clean, probably well maintained. Nasty, black as tar, probably some gunk in that motor and an owner that waited till the light came on or longer.

Ever been a recall to lower the oil change interval below 3K? Nope.

Ever been an OLM recall to shorten the oil change intervals because of potential engine damage? Yes.

Case closed.

[motorhead]

You this brings reminds me of when I had and old dodge aspen for a winter beater. Everyone said the slant 6 was bullet proof. So I decided to see how long it would run without even checking the oil let alone changing. It seized up after 22,000 miles one morning on my way to work. The funny thing was though, was when we towed it home I put oil in it and it had all day to cool , and I tried to start it. Guess what, it ran another 10,000 miles until I sold for $100 bucks. I bet our camaros wouldn't take that abuse.