Oil Life %?

[pyro4ik]

I check the oil life about every week on the display and its been hovering in the 40% range for a little bit now.......but up and down (41-44-42-etc..). Is that normal? I drive it about 25 miles a day....

[JD555]

yes. it changes depending if you are doing highway driving vs city. Same as the miles left to out of fuel. Get on the highway and it starts going up. Hit the city and it starts going down.

[granatl]

The exact computation of the oil estimator algorithm is a GM trade secret.
Generally speaking, it looks at the oil temp, RPMs, miles driven, etc. For example, if you're letting the oil get to ~215 degrees Fahrenheit, then it's boiling off the condensation (a good thing). If you're always driving at 6k RPM, it'll "wear out" faster than 2k RPM.

[Spec]

So they've got something in these things actually 'tasting' the oil to see if its good, or is it just calculating rpm and mileage and other factors, and coming up with its best guess?


I only ask this because on a recent oil change, I the car for the first time in its life warned me that I had only 4% left of oil life, even though I know I clearly changed it only a few k miles ago...


I could have forgotten to reset the system after the change - but not sure, I don't really remember.


I guess if it were 'tasting' it the car would not have to be reset manually after every oil change, right?


Curious how far technology has come...

[CamaroFred]

Originally Posted by Spec

So they've got something in these things actually 'tasting' the oil to see if its good, or is it just calculating rpm and mileage and other factors, and coming up with its best guess?


I only ask this because on a recent oil change, I the car for the first time in its life warned me that I had only 4% left of oil life, even though I know I clearly changed it only a few k miles ago...

I could have forgotten to reset the system after the change - but not sure, I don't really remember.

I guess if it were 'tasting' it the car would not have to be reset manually after every oil change, right?

Curious how far technology has come...

Of course it can't actually test the oil. It is supposed to use driving conditions and driving style, as well as other parameters.
Stop-and-go is harder than highway, cold and hot produces more wear than ideal temps. Throttle opening (higher load), average RPMs, high RPMs (racing), etc.

My ex, with her 3 mile commute, always showed lower life than my vehicle with 20 mile commute per mile. Over time, it was nearly the same. Which means her oil was changed with less miles than mine, though nearly the same number of days.

And yes, you probably didn't reset it.

[Talladega]

I always thought it counted the number of revolutions your engine made. That is how come of the first cars to have engine life indicators worked. But maybe they have come up with some better way to figure it over the years.

[Moto-Mojo]

Originally Posted by Talladega

I always thought it counted the number of revolutions your engine made. That is how come of the first cars to have engine life indicators worked. But maybe they have come up with some better way to figure it over the years.

It is an algorithm that probably monitors more systems thru the ECM than Apollo 11 had on the moon. You can bet they try to nail the change interval closely enough to help make it live through the warranty period. It’s kinda up to the owner to actually heed its warning.

[SharpOldNo7]

It always comes out to be around 7500 miles when mine says it’s time to change the oil. Funny how that always works out.

[Pluto]

Algorithm. If you plan on keeping your car, change more frequent than the manual suggests. Don’t care? Not going to keep it? Who cares. Do it whenever.

[redcoats1976]

i change at 5000 miles,even though according to the % meter its not close to that time.

[jravenfan]

Originally Posted by Pluto

Algorithm. If you plan on keeping your car, change more frequent than the manual suggests. Don’t care? Not going to keep it? Who cares. Do it whenever.

I have a 2003 Avalanche with 226,000 miles and always changed the oil based on what the algorithm told me. Still runs great.

[Pluto]

Originally Posted by jravenfan

I have a 2003 Avalanche with 226,000 miles and always changed the oil based on what the algorithm told me. Still runs great.

5.3? I have a 2004 suburban with the same engine and it takes an it’ll take an ass whipping too. My friends company has dozens of 5.3s with 300k+ on them and they changed the oil at 5k intervals. However, I’ve seen too many tensioners, oil pumps, lifters, etc go on the 6.2L. I’d rather not chance it is all I’m saying.

[lbls1]

Its ok, but check your dipstick level, and monitor your total mileage. It is safer to change oil in the lower mileage intervals, but if your level indicates full or above a half a quart, then you're fine but continue to monitor the level with both the dipstick reading and the oil life (stopwatch) monitor. Try not to add oil excessively unless you are below a quart or more; At that point you should change your oil body.

[gringo]

Full synthetic every 5-7K miles or every year, whichever comes first, works for me.