GM Oil Life Monitor

[DieselPower]

I forgot to add that the GM OLM includes a 20% saftey margin when it registers 0% life left on your oil.

 

[barrylndn]

Well, since we're talking auto-oil, I have a question for anyone to speculate about. Took in my grandmother's 2002 Mazda Protege, after looking at the last service date, and it was 2/14/06. Now, the thing is, the car only has 16,000 miles on it, and has traveled less than 1,000 since the oil change almost 2 years ago. However, I watched them drain the old oil, and it was as black and thick as really old diesel oil. What would cause this? I know it has sat for a long time, but with that few original miles, coupled with so few miles since the last oil change, is it normal to get that black and thick just from time?

 

[Wayne County Hose]

I for one, will continue to waste my money. Part of doing an oil change is also doing a chassis lubrication, visual inspection of underhood and underbody components, and checking all other fluids. I check my tire pressure, tire wear, brake pads, brake lines, etc. etc. I have prevented many problems and will continue to do so. So, will I save money by waiting until some of you say to change my oil? With small problems caught before they turned into large ones, towing bills saved, time and aggravation , I think that in the long run, I will continue to save my money and change my oil every 3,000 miles. You have to look at the big picture. If you do all the other things you should do every 3,000-5,000 miles and don't change your oil, good for you. This is just the opinion of a mechanic that has never blown an engine, tranny, rear differential, wheel cylinder, not even a water pump as I also change all other vehicle fluids yearly. *Footnote, racecar does not count.*

 

[sandman2234]

My Mother and I had an oil change conversation on the way back from the Gators beating the Seminoles football game. She said she was going to have to cancel her bridge game because the car needed the oil changed and she was right at the 3,000 mile limit. I asked her why she changed it that often, and she said because your supposed to. I suggested she get out her owners manual and read it. We determined that with her style of driving she would need to change it every 5,000 to 7,500 miles. She was happy, because she would be saving money and not having to deal with mechanics nearly as often. She has a garage change it, versus the quick change place, so hopefully they at least look at the underside of her car while dumping the oil.
Back in the 70's I attended an automobile seminar and a point was brought up about oil, that I have always remembered. Oil under normal circumstances gets better with use. What makes it go bad is the dirt and contaminants that are picked up in it's use. If we could filter it clean, we could use the same oil all the time, just filter the dirt out. The people that change the filter every other time amuse me because of that. During WWII, airplane engine oil was left in every other change, and just the filter was changed, and the oil level topped off. This was probably more of a "plane life" than a motor life in that period, though.
David from jax

 

[cp1969]

During WWII, airplane engine oil was left in every other change, and just the filter was changed, and the oil level topped off. This was probably more of a "plane life" than a motor life in that period, though.

I can't speak for any WWII engine other than the R2800 that was in numerous twin engine bombers and patrol planes as well as the Thunderbolt and Corsair. That's the only one I have any experience with, but most people would be aghast at what passed for an oil filter on this engine. I certainly was. It is nothing but a loosely stacked collection of plates and some very coarse Brillo pad material that would be lucky to stop a big dirt clod. Maybe it is because radials lose so much oil that filtering, let alone changing, oil is almost moot. Or it could have been that the life expectancy of these planes was probably less than the number of hours to the first oil change.

 

[Doc_Bob]

Well, since we're talking auto-oil, Now, the thing is, the car only has 16,000 miles on it, and has traveled less than 1,000 since the oil change almost 2 years ago. However, I watched them drain the old oil, and it was as black and thick as really old diesel oil. What would cause this?

That car is severe service. Even GM says to chnage the oil and filter every year no matter what the OLM indicates. Also, if the oil was thick, was it straight 30W or multivis?
Bob

 

[sandman2234]

The person who told me about the oil filter changes was probably working on B-29's, I think.
David from jax

 

[Redbug]

Just thinking about the OLM some more...I suppose it is calibrated for a "normal" oil? But what is a "normal" oil? Different brands of oil have different additive packages and ingredients. Some may wear or last longer than others. What about the person who uses a synthetic oil...such as Mobile 1? Don't they have longer usability limits?

There are a lot of variables here. But, I still wonder about the OLM. I understand the idea of the vehicle's computer monitoring engine use. But, what good is an accurate computer model, (OLM), when you do not have accurate data on the particular oil you put into the engine. It just becomes a WAG, with garbage in...garbage out.

Diesel and the Gang...does this make sense?

 

[mbrule]

My girl drives a 2006 Chevy Trailblazer with the 4.2 inline six. Holds 7 quarts of oil. I use whatever brand of Dino oil that is on sale and meets the required GM9024 (I think thats the number) specification. The car has almost 12000 miles on it and the oil change indicator has yet to lite! I am a 3000 mile changer, and have changed the oil in it 6 times already. I changed it immediatly upon taking ownership as it had been on the dealers lot for a year, then at 1000 miles then every 2500 to 3000. I have always been a 3000 mile changer and have never had a problem. Just my .02.

 

[JSharp]

Just thinking about the OLM some more...I suppose it is calibrated for a "normal" oil? But what is a "normal" oil? Different brands of oil have different additive packages and ingredients. Some may wear or last longer than others. What about the person who uses a synthetic oil...such as Mobile 1? Don't they have longer usability limits?

There are a lot of variables here. But, I still wonder about the OLM. I understand the idea of the vehicle's computer monitoring engine use. But, what good is an accurate computer model, (OLM), when you do not have accurate data on the particular oil you put into the engine. It just becomes a WAG, with garbage in...garbage out.

Diesel and the Gang...does this make sense?

The OLM is calibrated for the recommended oil in a given vehicle. They assume you won't be using an oil that doesn't meet the minimum specification, and that any oil that does meet the minimum specification be at least adequate.

Some oils you might be able to run farther but it would require you reset the monitor then watch it until it reaches the percentage you've determined is OK.

It also won't protect you if you try to use something wrong that doesn't meet their spec - like that SA rated 50 weight you got on sale for $.17 a quart...