Two part oil change observation question

Paul Shuler · May 10, 2016

I have one of those remaining oil life monitoring systems on my 08 Duramax. I changed my oil on 1-29-16 and noted a few weeks ago that I had about 45% oil life left. I thought that to be about right. Then yesterday it popped up a warning change engine oil soon! I checked and it said no oil life left. I have never had it do that before. I change it most of the time when it gets around 30%. I thought that was awfully fast for it to go to 0%. Almost no highway driving on this change or towing. I had gone about 2,900 miles. I usually get around 6,000 miles between changes going by what the sensor tells me. I changed it of course to be on the safe side. Didn?t know if anyone else has had the same experience. Part two. Every time I change the oil it bothers me that the front of the pan is a good 1 1/2 lower than the back of the pan where the plug is. No way to get all the old oil out. I would guess maybe a 1/2 qt of the old oil stays in. Seems like a bad design. I will try and attach a photo of the pan. It?s not mine but one I found on the net.

D beatty · May 10, 2016

I don't trust those sensors and change oil by mileage.

smash59 · May 10, 2016

Here is what I have noticed on the Chevy oil change system,and I could be wrong. The system I think goes by hours not mileage. On our work trucks, the bosses truck goes 6000 to 7000 miles between changes. My truck that is that has a lot of idle time miles driven in fields goes about 2500 miles between changes. I know there is a hour meter in the computer. Just my thought.

Tiger Joe · May 10, 2016

The GM oil life monitor is actually a very complex algorithm that takes into account many factors mileage being just one of them.

Have you done any tuning to your truck, or any playing with deleting the DPF? that can cause havoc on the oil life system. I've also heard of trucks going to 0% when regen'ing a lot.

as for the oil pan, it probably holds about a cup of old oil. If it bothers you, there is an aftermarket pan called the "Banana Pan" that eliminates that problem. realistically, its a non issue since your truck holds 2 gallons of oil.

Russ from MN · May 10, 2016

You said almost no highway driving, that is your answer!

pete black · May 10, 2016

Read an article years ago that said it factored in engine rpm's and oil temperature as well.

Bob M · May 10, 2016

Paul - Like Tiger Joe says the GM oil monitor looks at several different variables to calculate remaining oil life. Variables include a crank revolution counter, number of cold starts, engine revs accumulated while running with oil below operating temperature vs running at optimum temp, some sort of average engine load calculation (a heavily loaded engine "uses up" oil life faster loaded engine), and probably a few more.

I agree - short trips, especially in cold weather, will dramatically shorten calculated oil life. For example my wife's Chevy Impala (driven mostly long distances at highway speeds) routinely displays the change oil message only after 9,000 - 9,500 miles. But the elderly woman across the street with the same car barely gets 2,500 miles before the message appears (she drives only every a couple miles to the store, church, bingo, etc). Her car probably NEVER gets fully warmed up.

Incidentally the ScanGuage II aftermarket automotive computer I have on my wife's car can peek into my car's ECM and display in real time the calculated % remaining oil life.

David G · May 10, 2016

Mileage really mean nothing, the computer does a better job to compute effective mileage.

Andy Martin · May 10, 2016

You're supposed to put it on a grain lift to change the oil.

That is an interesting pan design. I wonder what the engineers were thinking? If they were actually thinking. It would seem that it would be nice to let heavy sediments drain out during oil changes. My Cummins drain plug is inset a little preventing all the oil from coming out as well. Not as bad as the Chevy but still the same idea.

Ozlander · May 10, 2016

I think you need a new oil pan.
Somebody high centered on the pan.

Bob · May 10, 2016

"I don't trust those sensors"

AFAIK, there's NO "oil change sensor" not to trust.

Thus ain's "Star Trek", where they had sensors for everything!

T in NE · May 10, 2016

No, that's how they made them. No idea why.

But it is a light-duty engine, so....

D beatty · May 11, 2016

I have one of those sensors on my Chevy Impala and at 4,000 miles it says I still have 85% left and oil looks dirty and starts using oil if not changed. I have a BIL that also has an Impala and changes oil about every year to year and half and oil sensor says he still has 45% oil life left and oil looks like mud. I will never change oil by what oil sensor reads.

Two part oil change observation question

Paul Shuler

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D beatty

Well-known Member

smash59

Member

Tiger Joe

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Russ from MN

Well-known Member

pete black

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Bob M

Well-known Member

David G

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Andy Martin

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Ozlander

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Bob

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T in NE

Well-known Member

D beatty

Well-known Member

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