What does "Oil life remaining - XX%" really mean?
 

Hi Folks,

Doing an oil change on my 2009 C6...the "change oil" message came on.

I've read the excellent oil change pdf here. My question is, what does "100% remaining oil life" typically mean? 10,000 miles? 5,000 miles? 3,000 miles? etc. (I drive like an old lady -- who is very occasionally chased by demons :nono: )

I'm terrible about changing oil, and my old 1984 Supra now has 325,000 miles on it with no engine problems at all -- never touched it -- and filthy black old oil most of the time. Had it since 1988 and it still starts and runs like a clock. Honestly, I think this whole "oil change" thing is mainly for the oil company's bottom line...:eek:...but that's not my point.

Mobil 1 should take the engine to at least 15k miles, with average driving, from what I've read.

So how many miles does "100%" or "Change Oil" mean? For my 2009 C6 -- with average driving :flag: -- According to GM?

Thanks,

Fred

"Mileage" has nothing to do with the oil life monitor in the car. It all depends on type of driving and the conditions the engine sees. Could be 15,000 miles or 3,000 miles to go from 100% to 0%.....all depends. The % you see in the DIC is just something for you to gauge what's going on and what to expect.

The algorithm used for the oil life monitor is a calculation taking into account ignition cycles, engine RPM and engine temperature. Short trip stop and go driving and sudden start acceleration are the worst case scenarios as they will result in more ignition cycles, higher temperatures and higher rpm. This will drive the oil life down dramatically.

:thumbs:Many factors go into the way the system works. Temperature,speed,load ,idling,stop and go etc. Somehow,with all these varying factors your oil is analyzed and its service life is calulated on all these factors and a percentage of life is displayed. You cannot directly correlate it to milage. Though you could reasonably assume that at 10,000 miles and the system shows 50% that continued driving under similarconditions as you have been that another 10,000 is warranted. But that may not be the case. Stop and go for example compared to high speed highway driving. What with computers and all the other technology we have in cars now this system provides us with a better system of when it is time to change the oil. Hope this helps. PS. GM started using this system on the Eldorado back in the late 80s.:cheers:

For me it is 8,000+ miles


Elmer

For my Z06, 100% (actually 99%) equates to about 7500 miles based on my driving environment. My wife's DD 2010 CTS Wagon appears to be good for 10,000 miles.

driving around 9000 - 10000 miles a year, and change oil every six months at a minimum. warranty requires atleast one change annually. never had my oil monitor go below 50% with the mileage shown.

Although the remainder of what you said seems to be pretty accurate, the oil is not analyzed. It's all just calculation.

Good answers -- thanks everybody.

I'm a big believer that these decisions are not made purely by the engineers. There is a lot of money to be made here, and these decisions probably start in the boardroom, in meetings between GM and Mobil. Then -- the lawyers get involved. :willy:

So it's good to hear some real-life experiences on this one. I'll monitor these numbers on my car -- I think I'm a pretty easy driver, all things considered. But maybe I'm not, it will be "fun" to see what my numbers come out as.

I'll say one thing -- times have changed since my first car, a 1959 MGA!
:cheers:
Fred

:iagree:

And I'll just add that a real analyzation would probably show that there's plenty of life left in the oil, especially a synthetic like Mobil 1.

But -- "them's is just words"

Cheers,

Fred

Cold winter, short trips, urban driving; I can use up 100% in about 5,000 miles.

Long trips on the interstate during summer; I can get over 15,000 before getting to 0.

As they say, YMMV.

There should be a "Change oil Now" light on all cars, and if you pass a certain mileage the car shuts down, then engines will be warranted for 200K.

I will keep changing my oil at 2K on my daily drivers, and 1K on the vette, until I can not afford to do so.

I've had Blackstone Labs analyzing my used oil, and after 24,000 miles they are still recommending the next change after about 7,000 (50% remaining). But, lots of people run it down to 0 every time from day one, and still get long life from their engines.

Hard to predict what is really the best compromise.

I pay no attention to the DIC oil life reading. It's always around 30% when I change it.

I change oil every 8k miles or 1 year, which ever comes first. Actually, they always come about the same time for me.

Some BMW models had this feature until owners started to complain.

I change mine at 25%. Usually around 8k. My truck had 14.5k (09 Silverado with 6.0) before I was told to change the oil. I did the change myself and was amazed how clean the oil looked after 14.5k. The old saying to change every 3k is such a waste of money.

oh boy....this could get bad in here.

You are going to get those who claim anthng short of every 2K or less and you are an idiot who knows nothing of maintaining a car. Although I always respect anyone's right to do whatever they want with their vehicles, they are playing right into the dealers/oil companies/service provider's hands. Follow the DIC percentage and read your manual to find the upper limit....it's not hard.

I service mine on all three of my GM's when it dips below 25% or at least once a year. My CTS and my Acadia never go below 25% during the year, so the one-year rule applies for me.

The warning was on the 06 Vettes, according to my owner's manual, but no engine shutdown.

I have not checked the owners' manuals for later models.

I just changed my oil at 2% remaining, and it has been 12,500 miles. She did not burn anything in those miles.

I don't really have a side in this particular holy war, but I wonder what effect engine modifications have on the algorithm. I'll probably just change the oil when the % remaining gets low, but if I really want to know I guess I'll send a sample off to Blackstone.

Do any of you guys make the crazy assumption that those high paid GM engineers know what they're doing.........and just change the oil when the DIC commands? I really don't like changing oil. It's not high on my list of weekend activities to plan for. I know this sounds crazy as hell, but I change the oil when the DIC tells me it's time and use the recommended oil. I know....that's nutz:cheers: