GM Oil Life Monitor

[Doc_Bob]

Originally Posted by Kaliburz

I try to change my oil twice a year in the two/three vehicles I use regularly. Then again, I run 15W-40 in all my engines (minus air cooled, that gets 30wt).

Sounds like a good plan.
Bob

[On-Site Oil Analysis]

OK for all of you who think you want a a GM oil monitor let me be the first to tell you that you don't. It is NOT a diagnostic tool in any way shape or form. It has no value as far as measuring how far gone your oil actually is additive wise or how dirty your oil actually is. It only estimates the condition of it base on a advanced algorithm that GM came up with based on engine temperature, cylinder strokes per second over a length of time. Thats it folks nothing more Sorry !!!! So to answer your next question can it lie to you yes it can. If you use cheap oil it can lie or non API oil it can lie or if their is something wrong with your vehicle it can lie. Now if your vehicle is working perfectly does it work sure. But if you drive in severe dusty conditions I wouldn't trust it. Because it doesn't know that this is the case etc.
Again I am not saying GM didn't build a good math equation they did. Just that they aren't actually sensing or measuring anything in or about the actual oil itself.

As a Oil Analysis Guy I am Positive about this fact Ask your GM rep if you like.

[On-Site Oil Analysis]

Instead of changing your oil twice a year and hoping that is good. Run a sample of your Oil up to a local shop or Speedco Speedco Home Page or Rush trucks someone who does oil analysis and for $15 you will know for sure if you are changing your oil often enough otherwise you are just guessing and possibly doing damage to your engine. Also mark down how many miles or hours on the oil so that if it comes back bad you know to run it less next time and try again. If it comes back good you know not to go over that point with out questioning it with another oil analysis.

[MikePA]

Originally Posted by On-Site Oil Analysis

Just that they aren't actually sensing or measuring anything in or about the actual oil itself.

Since you're new to TBN, you might not have had a chance, or the time , to read all the posts in this thread. This was mentioned way back near the beginning of this thread.

[deere755]

Oil is cheap, engines are expensive, I change every 3000 no matter what the oil life monitor says. Just my philosiphy

[FlaDon]

Originally Posted by gemini5362

I am sure someone will correct me on the numbers and it was a long time ago. I believe when MOBILE 1 came out the literature called for oil changes every 15000 miles. They recommended that you change the filter after 7500 miles and then change the oil and filter at 15,000.

My porsche boxster came from the factory with MOBILE 1 installed. This is a high performance engine and Porsche reccomends oil changes every 15,000 miles.

I read the post about the complexity of todays engines and the tolerances of the oil passages etc. I remember an old article I read about Honda Goldwings. this is a motorcycle engine set up for High RPM usage and the transmission and engine both shared the same oil. Honda in a test ran a goldwing without doing any oil changes. After 100,000 miles on the engine they finally tore it down and the wear and tear on the engine was not severe enough to warrant replacing any of the engine including the rings.

I do have a question for some of the posters that are so worried about wear and tear on their engines due to oil problems. According to everything that I have read the worst oil related problem that you have on an engine is starting it after it has been sitting for a while even as short a period as overnight. During the initial time that you start it you have parts that are rotating with a metal to metal surface until such time that the oil is pumed into that region. They make electric oil pumps that you can turn the ignition key to the on position and that starts pumping oil through the system. You can leave the key on for a short period of time before you actually engage the starter motor. How many people have installed one of these systems on their vehicle ?

On most stationary/Railroad Diesel engines, that is common. On the Detroits we had at one place, we didn't. Oil change was at 300 hours, ( set by testing ) with 2 qt of oil added every 24 hours between changes. Life span of the engines was 10,000 at worse with engines running past 14,000 hours the rule. Crank wear at 14,000+ hours was nill. Ring and piston wear was the problem. Rings wore lands and grooves that mirror imaged the lands and ports in the cylinder liners. Engine overhaul time was when the engine would suddenly go from the 2 qts to 8 qts in 24 hours. This was with oil pans that held 36 qts on an oil change.