Oil Life

The newer GM vehicles have a feature built into the electronics, an algorithm that senses and calculates oil life. Some of the GM literature says it is not uncommon for a vehicle, under certain circumstances, to put
as many as 15,000 miles on an oil change.
I'm not sure I trust the 15,000 miles but at the same time, I want to be as cost effective and enviroment friendly as possible. I put on a lot of highway miles and have been changing at around 6,000 miles.
I checked my oil life reading, using a Tech II and with 6,000 miles on the oil change, I show it still has a life of 47%.
Does anyone have any experience on the accuracy of this sensor?
I prefer not to get into a flame war over 3,000 mile oil changes, I am trying to gather info on the accuracy of GM's oil life sensor.
Thanks
Paul P
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as
If you really want to know what is happening with your engine/oil, get into an oil analysis program.
Diamond Jim
"The Old Devil Dog"
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"Paul Proefrock" wrote

as
There is nothing cost effective about replacing an engine well before it's time, or can I see anything particularly environmentally friendly about replacing an engine before it's time. Most of the used oil in our city is recycled, I believe. I'm sure it's probably put to good use the second time around. I really don't buy the line that the manufacturers care very much about being environmentally friendly. What I do believe is that they want to "appear" to be EF. So in the short term, they "appear" to be green.
> Does anyone have any experience on the accuracy of this sensor?
Accuracy compared to what?
Ian
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On Mon, 10 May 2004 02:02:20 GMT, "shiden_Kai"

I would think "accurate" compared with the actual useable life of the oil.? What other parameter would matter given the context of the question?
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"Bob Muse" wrote

How much coolant is in the oil? How much fuel is in the oil? There are more reasons to change your oil in a timely manner then just it being "dirty".
Ian
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On Mon, 10 May 2004 22:08:08 GMT, "shiden_Kai"

It seemed to me that all those things would figure into a guess as to how "accurate" this little light is. Probably be scary to see how simple its parameters are.
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wrote:

If it works within the parameters set by the manufacturer, then it could be said that it is accurate. However, if it allows me to go 15000 miles between changes, then I'd have to say the manufacturers standards are much lower than mine. H
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To the best of my knowledge and from what I've read in the manual of my new truck, there is really no "sensor" so to speak. The Change Oil message is triggered by one of three things, whichever occurs first: The mileage hits 10,000; the engine revolutions reach some designated total number (not detailed); or the hours reach some designated amount (again not detailed). If the brain senses high engine load (including extended use of the Tow/Haul mode) or a great deal of idle time then it reduces the trigger points and tells you to change the oil that much sooner. There is nothing inside the motor physically looking at the quality, viscosity or particulate content of the oil itself - just a glorified timer/counter.
FWIW, I change my oil with synthetic every 5,000 miles (long before the oil change message comes on), ignore and reset the message when it does come on because I'm well ahead of what it's telling me, and recycle every drop of used oil I can. I've seen how they recycle oil on board ships with a high-speed centrifuge. Used oil goes in looking like thick black mud and comes out golden clear. We would then test it's viscosity, thicken or thin it ad required, and add anti-friction and other additives as needed. In this manner, oil stock could last through decades of use.
Cheers - Jonathan

as
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The thing to remember about motor oil, is that base oil has the look and consistency of canola oil, the additives make it thicker and so on. When oil breaks down, it is the additives that go. Cam

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For sure, additives are used up over time. But when conventional oil breaks down you get loss of viscosity. Then it's fubar'd and generally so are your bearings if the oil is not replaced soon. And coolant in the oil is the fastest way to seizing a bearing other than running the poor bastard totally out of oil.

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