i remember reading this ginormous post about the algorithms used in the patented GM oil life calculator. the basic deal is that it measures the amount of a certain chemical in the oil & based on the mileage, throttle position, & cumulative engine revolutions, it gives you a reading of oil life left. i don't know what years that is effective for, though.

 

maybe this will clear up what i'm trying to say: approximately 3k miles after my oil change, my change oil light came on in the message center. i promptly reset the oil message and have driven about a thousand miles since then and the truck has not told me to change my oil yet, so i'm pretty sure that the older trucks are set-up differently from the ones that actually give you a percentage on oil life.

 

There is no sensor that analyzes the oil, it is strictly a calculation based on the parameters that I listed.
Of course it has not told you to change the oil, you reset it! Your computer thinks that you have 1000 miles on fresh oil. Again, there is nothing that analyzes the oil, the only way that the computer knows that you change the oil is because it believes you when you reset it. The percentage is simply a guess, based on how you have been driving since you lied to the computer and reset it.

 

I can't seem to get my oil meter to reset. Anyone know exactly how to do it. I've tried about 20 times and I guess that I'm just handicapped.

 

On my truck, I turn the key on and quickly depress the gas pedal 3 or 5 times in a row (can't remember exactly)...not sure if it's the same for an 05...

 

what? we have to change the oil that goes in the engine? It's supposed to be good for 100,000 miles, right?






I change mine when it looks brown. That's my science. When it looks dirty, I change it.

 

Same thing with your underwear billy? That is assuming you wear underwear.....

 

commando!

 

I thought that you were in Depends all ready Bill?

 

I have an 03 with oil life, instang mpg, stop watch....everything on my cluster. It definatly goes on the mileage you drive and the rest of the measurments that MikeGyver posted. I endup reseting mine 2-3 times during my oil life. I run AmsOil with the AmsOil filter and usually add 1/2 a quart every 5000 miles to keep it topped off. And usually change it between 12k-15k. Amsoil says that in extream conditions its good for 17.5k and normal conditions 25k. I just figure the way I drive my truck and the abuse it gets ill change it before Amsoil recomends. Besides using the Amsoil filter my oil is still golden brown at 5k.