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If GM thinks that 364 days on the oil is ok but 366 days is too long, they should program the system to follow the old parameters and ignore the calendar until maybe the final week.
It seems like some people's driving habits have them paying the "penalty" for time and miles combined.
Not a problem for me at about 15k per year, two changes per year.
That's essentially how I wished it would perform. But it could use the latest algorithms developed for the C7 but just take the time element out until like you suggested the final week or two. That way you could watch how your driving style is affecting the oils life over the course of the year and still get the reminder at the end of the year to change the oil if you don't put that many miles on the car every year. If it worked that way it would be providing us with more information about oil degradation.
Is the car going to tell on you if you drive it one extra day, week, or month. I think mine hit 0 one time, but it never went into negative numbers. It just showed zero until I got around to change it.
If GM thinks that 364 days on the oil is ok but 366 days is too long, they should program the system to follow the old parameters and ignore the calendar until maybe the final week.
It seems like some people's driving habits have them paying the "penalty" for time and miles combined.
Not a problem for me at about 15k per year, two changes per year.
Originally Posted by Walt White Coupe
That's essentially how I wished it would perform. But it could use the latest algorithms developed for the C7 but just take the time element out until like you suggested the final week or two. That way you could watch how your driving style is affecting the oils life over the course of the year and still get the reminder at the end of the year to change the oil if you don't put that many miles on the car every year. If it worked that way it would be providing us with more information about oil degradation.
Not to belabor the point BUT for those who mostly make short trips it will show less time left than the ~8% reduction per month. Using “miles” went out when they started to developed this much more sophisticated method. However GM and many others recognized that the one year max was needed as oil does repeat additives. They said “change at one year max in my 1st, 1988 Vette owner’s manual. Many folks did not bother to read the manual (as is obvious from not just this Thread but many others) so my 2008 C6 still showed 30% oil life left at one year. It was my job to know that it needed changing. What about the owner’s who never open the owner’s manual?
So for those who mostly make 3 mile short trips looking at the OLM will show a change needed in less than one year. For those who put on ~7500 or more miles/year suggest you not look at the OL display so much! I for one would NOT like the display to show ~5% oil life left a week before it happens!
LOL, I guess if your engine is burning that much oil, there's no need to change it. As an old engineer once told me, "the solution to pollution is dilution."
I'm also amazed at many of the responses here.
I owned a Corvair back in the 70’s and it lost a quart of oil every few weeks. Everytime I checked the oil is was as clean as if I had just changed the oil. Come to think of it I don’t recall ever changing the oil.
I owned a Corvair back in the 70’s and it lost a quart of oil every few weeks. Everytime I checked the oil is was as clean as if I had just changed the oil. Come to think of it I don’t recall ever changing the oil.
I agree with the OP. We have two Lexus', and they advise to change the oil every 10k miles - no time frames. For us, that can be over two years between changes, and it hasn't resulted in any problems. The cars are an '07 with 92k miles, and a '10 with just shy of 70k miles (will have its oil/filter changed within a month).
I will also follow the 10k miles schedule on the C7 after the warranty expires, however, I have no doubt the car would have no oil-related issues at the 10k mile mark regardless of what the OLM advises. In almost 60 years of driving, obviously most of them prior to pre-synthetic oil availability, none of my dozens of cars dating back to a '58 VW has ever had an oil-related problem.
Lexus does not advise no time frame with their oil changes. The service schedule for the older cars will be 5,000 miles or 6 months and for the newer 0-20w cars, 10,000 miles or 12 months. Even if their oil change counter ignores times, Lexus clearly requires 6 month (or 12 month) oil changes for warranty coverage, and every service schedule/FAQ they have lists a time frame.
You are correct however, that with modern oils, it is very unlikely to have oil related issues simply due to the oil being more than 6 or 12 months old. From reading a bunch of analysis on the Bob site, it seems stretching to 2 years doesn't cause a problem in most cases. However, there was one example with only very short trips that the oil was pretty much shot after a year. The manufacturers fr both vehicles and oil are of course going to be conservative. If oil related failures go up a little bit going from 12 months to 18 months, particularly for those "short trip only folks" that's enough of a reason for them to stick with 12 months.
I don't blame GM for the 12 month thing, and glad it is now part of the OLM. I also don't disagree with any out-of-warranty owner who chooses to extend past the time-frame a little bit.
Seems to me that while the number of miles before a recommended oil change has varied over the years (and model of car) that the one year limit has been with us for what seems like forever (I think since I've been driving and that's around 60 years). With the major advances in motor oil technology, you would think that that one year limit is out of date. For a while a few years ago BMW extended their recommendation out to two years but then put it back to one year.
I don't think anybody is objecting to the oil change interval (either time or operating conditions based) but it is the way GM chooses to display it now. Previously the OLM provided a pretty good indication of how operating conditions were impacting projected oil life but now that picture has been muddied by the placement of a linear time based factor into the OLM percentage life reading. I am FINE with it indicating either 0 or a "Change Now" message at the end of one calendar year but not with factoring this linear reduction into the projected oil condition. The best reason for doing this method is to prevent customer uproar over an OLM indication that rapidly drops to 0 at the end of the calendar year; it would have been very easy to program instead a warning that shows oil must be changed in 1 months (or 2 weeks, etc.) when the percentage life is still high as year end approaches. Lord knows they have programmed enough of these types of warnings in regarding DEF level in current diesel pickups so it isn't breaking new ground.
This OLM is part of the same goofy philosophy that results in the coolant temperature gauge of my 2018 GMC Sierra Denali 2500HD diesel sitting fixed on 210 degrees even thought the actual temperature may be dropping into the low 180 range or increasing to near 220 as operating conditions change. This was chosen to prevent customer concern over a gauge moving around to actually display real conditions and is the same stupid approach Ford took for years with many of their products. Hopefully GM doesn't start turning all of the gauges into glorified idiot lights where the gauge simply indicates normal until the parameter is at the upper or lower critical level because the behavior of a real gauge is often helpful to a knowledgeable owner taking corrective operational or maintenance actions before a real problem occurs and most less knowledgeable types are going to ignore the readings anyway until fluids or parts are expelled from the powertrain.
If you don't like the way it's displayed, stop scrolling to the OLM display. It will tell you when it's time. The only time I have any idea what percentage is left is when OnStar sends me an email.
On the needle gauge temp display issue, I've noticed the digital readouts are quite precise in this display. This is the only display I ever use because everything I want to see is right here. I don't worry about what the OLM says.
You are correct however, that with modern oils, it is very unlikely to have oil related issues simply due to the oil being more than 6 or 12 months old. From reading a bunch of analysis on the Bob site, it seems stretching to 2 years doesn't cause a problem in most cases.
Because my C6 was used and I only drove it about 4-5000 miles a year, I was doing 2 year oil change intervals with it and every oil analysis I had done on it showed that was safe, that car was never short tripped. That being said, I am going to be driving my C7 a lot more often (have already gone 8300 miles since I got it last December) so I doubt I will ever even come close to going one year on the oil, it'll be more like 6-8 months.
With the older OLM setup it was easy for me to have a very good idea based upon the display and my anticipated driving when I would need to prepare for an oil change (i.e. OLM shows 40% left and I am planning on a 2,000 mile trip) but with the current system it might read 10% under identical engine operating conditions because of the time component. The old OLM setup was far more useful to me so I don't object to the OLM display showing up but I prefer the most accurate information. I suspect at some point GM will just go to a change oil now message and drop the percentage readout in the name of simplifying the consumer interface.
I hope that the Corvette platform continues to use the actual information for its engine gauges because it is a performance vehicle but I also would have suspected the same for a GM platform with a 31,000 pound GCWR that is sold to a lot of commercial users so I don't have as much faith in GM user interface decision making as I used to have.
I guess I'm still old school, at least when it comes to my other vehicles. I get the oil changed, and the shop puts a plastic sticker on the windshield that shows the date the oil was changed, and the mileage when I need to get it changed again. Of course now, the shop will say I need to get the oil changed in 3,500 miles like in the old days, but I will wait until 5,000 miles before I change the oil again. If I am going to take a 2,000 mile trip, I will look where those miles fall when my next oil change is due. If there is an overlap, then I will change my oil before the trip. If it is close where the 2,000 miles exceeds my change interval by a couple hundred miles, then I will change it when I return from my trip. I normally change my oil in my Corvette in the Spring since I drive through the winter if it isn't snowing. If the OLM is at 75% in the Spring, I will change the oil anyway. If the OLM shows I'm at 5% in January, I will still wait until the Spring to change the oil. And Spring can be March or April. It all depends on when I have time to get the oil changed. I doubt the motor will explode if miss the OLM timeclock interval.
It's astonishing to me that folks place so little value in a much more sophisticated OLM algorithm that takes into account things like idling, short trips, and engine revs. Those variables are by far the most important in determining whether the protective additives are depleted making it advisable to change the oil.
It may not be as "predictable," but it certainly is a more accurate estimate of oil condition. I'll take reality over predictability any day. Moreover, the count-down percentage does give folks ample time to plan ahead.
Patman, Thanks for your response. I will hold off on oil change and do it in spring. Checking mileage from last change was 1050 miles ago and not many short trips.Thanks again Dave
So I normally change my oil every year when I get my car inspected. And my car usually has 3500 to around 4500 miles per year at the time of inspection. As a comparison at that point my C6 would have said I had ~40 % or more life left. So this year at about an 11 month interval since the last change and 3000 miles driven, I'm down to 2% life left on the oil. That's absurd.
What's absurd, is you deciding to change the oil @ 3,000 miles. Not, that the OLM is absurd.
It's astonishing to me that folks place so little value in a much more sophisticated OLM algorithm that takes into account things like idling, short trips, and engine revs. Those variables are by far the most important in determining whether the protective additives are depleted making it advisable to change the oil.
It may not be as "predictable," but it certainly is a more accurate estimate of oil condition. I'll take reality over predictability any day. Moreover, the count-down percentage does give folks ample time to plan ahead.
Your post proves your inability to think for yourself. 100% synthetic oil with 0 miles on it, isn't worn out on Day #366, any more than it was still good at Day #365. That's just nutzo!
If GM thinks that 364 days on the oil is ok but 366 days is too long, they should program the system to follow the old parameters and ignore the calendar until maybe the final week.
It seems like some people's driving habits have them paying the "penalty" for time and miles combined.
Not a problem for me at about 15k per year, two changes per year.
Your 100% synthetic oil is still good at 15K. Properly filtered, it's good for a lot more than that.
You should probably make an enquiry with GM as to answer your question as to why your oil is good at 364 days, yet bad, on day 366. #LOL! Good luck with
that one! The answer is; "The OLM was installed so people without reasoning capabilities, or, the ability to think for themselves, don't question our system."
10-10-2018, 06:34 PM
I think mine hit 0 one time, but it never went into negative numbers. It just showed zero until I got around to change it.
