SabrToothSqrl

On my 2009 Tahoe, I can pull up a % of oil life remaining. where it starts at 100% and works it's way down to 20% or 0%

I know my 2012 Jeep has an Oil Life Monitor system, but how can I tell where it's at?

Do I change the oil now? in another 5 months? how do I know when to change it?

I usually change mine in the Tahoe at 20% Oil Life Remaining... but the jeep is keeping me in the dark :(

thanks

Jiblet

According to the manual, when the OCI comes on you should change the oil within 500 miles.

The OCI is pretty conservative, it is designed for conventional oils, so you're probably OK if you consider the first time the OCI dings to be about somewhere around the 20% remaining life.

It's all estimates anyway, the oil isn't actually measured or tested. The OCI computes a bunch of parameters to make an estimate.

If you're using a top synthetic you can probably go a lot longer than the OCI indicates, you might only be down to 50% life. The only way to tell is to have a used oil analysis done (e.g. Blackstone labs)

If the OCI goes off after, say, 2000 miles, I'd change it in 500 miles or so. If it goes off at 5000 or more, you're probably ok to put another 1000 on (assuming the same driving conditions).

Of course, stay within the requirements for your warranty.

rob_engineer

I think you are going to see the oil message come on sometime between 6k and 7k miles. I pay no attention to that. I change my oil every 5000 miles, then I simply shut off the oil indicator when it comes on since it has little to do with what is actually going on with the oil. Many people on this forum also use the 5000 mile change interval. Very easy to remember.

SabrToothSqrl

yep, that's exactly what GM does as well, it's all based on computations, run cycles, temp cycles, etc.

I just wish I knew when it was getting close. I guess 500 miles is enough, but still I like to see a % on the display like my GM does.

I run full synthetic in mine (or will when I change it). (Don't know what was last in it).

We do the 5k oil and tire rotation on the wife's car, but the Tahoe and the Jeep have tools to let you know when to change it, which works for me

I think my Tahoe went at least 8k before it got down to 20%! the dealer near us still tries to insist on 3k changes. Apparently they miss the income!

(I do all mine on my own) and every oil change, I rotate the tires too... damn 35s will kill me yet.

Ryan0260

I never go by the computer. I have always went by mileage and time..

Jiblet

Consider an imaginary 90 engine hours:

Car 1:
If you drive 90% of the time on the highway let’s say 1500 rpm an hour.
The engine sees 90,000 revolutions in that hour and drives 60 miles.

Car 2:
City driving with 90% of your driving in 1st, 2nd, and 3rd gear, taking 3,000 rpm on average. That's 180,000 revolutions of the engine in 1 hour driving 30 miles.

Extrapolating to 90 days:
Car#1 8,100,000 rotations and 5400 miles
Car#2 16,200,000 rot. and 2700 miles

This approximates 1 hour of driving a day for 90 days.
Car #2 sees twice the engine rotations of car #1 but only half the miles driven.
(example modified from a discussion on: http://www.bobistheoilguy.com/forums...1735142&page=1 )

That’s only roughly considering RPMs, engine hours, and miles driven.
There are many more factors that come into play for the OCI’s.
The point is that mileage is not a very reliable indicator of oil life.
Consider a thousand miles of hard, dusty wheeling verses a thousand miles of straight highway cruising.
Or a thousand miles in a Klondike winter vs. a Texas summer.

SabrToothSqrl

yep. I love the OLM. they take into account driving habits, outside temp, engine temp, starts, fuel types (if you have a flex fool car) (yes, i said fool).

way smarter than mileage based.

the only real way to do it better would be a true oil sensor that could read impurities, but the computer should come close.

I know towing makes a big difference on my Tahoe. I drive fairly gently, so I get more miles per oil change.

I can't, however wait until all of this is as irrelevant as leaded gas...

Soon as Tesla makes a SUV, I'll be placing my order!

Flip94ta

I've also liked the GM OLM over the years, we have/had three cars with it and have 145K, 88K and 56K miles. The only issue thus far has been with our 2010 Equinox, they overshot the program on that one and I checked the oil at 6.5K in to a change with 30% something percent left and the oil was a quart low and gray. It showed no prior issues in the previous 45K. The oil was toast. So I changed it ASAP and I'm sticking closer to the 5K rotations now. When the oil changed at 55K was the first time it's looked decently clean since that issue. My pentastar looks spotless in comparison at 14k.

Interesting GM sent us a letter stating a reprogram for the OLM was needed because of this. I'm just hoping no damage was done. I really liked the OLM on our 4.2L in our Rainier, it held six quarts and would go 10-12K between changes. I would change the filter, top off and rotate around 6K in for extra insurance. That was a money saver and ran really strong when I traded it in with the 145k.

Jiblet

Odd that the oil was gray. That seems like water contamination. I'd check inside the radiator (just look into the open cap) for any oil floating around. My first thought was headgasket.

The OCIs generally are only algorithms that compute an estimate based on a bunch of parameters like run-time, various temps, RPMs, etc., etc., but they don't actually test the oil or measure the level. So it's a good idea to regularly check the dipstick.

shabbernigdo

I run syn so i just change it every 5k or 6 months which ever comes first.