Oil Life Monitor

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69
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NYC
Thread starter
I'm confused, I have a 2010 Cadillac CTS with the 3.0 motor. I changed the oil using full Synthetic. That was 4K ago,. My oil life monitor says I only have 37% life. Do I believe it? Thank You
 
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1,395
Location
UT
That seems about right. That extrapolates out to about 6300 miles before the OLM will be telling you to change the motor oil. As kschachn points out, the OLM doesn't take into consideration what type of oil you put in the crankcase. If my memory serves me well, the GM OLM algorithm takes into consideration engine revolutions and engine temperature to calculate engine oil life.
 
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765
Location
TX
Sounds right if you're driving the car hard(frequent short trips) or it's been 6+ months since you changed it.
 
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1,570
Location
WA
You will be about 6500 miles oil change interval based on your OLM. I don't have olm but when I use dino, I go 1-2K below the recommended oci. When i use a good syn , I may go up to 1K over the recommended oci. If my oci is 6500: Dino will be out in 4500-5000 miles max. I guess I do this no matter what the OM says. Full syn will be out about 7500 miles. 8K max. Again I do this no matter what OM and/or oil jug says. e.g. "15K miles" M1 EP that I use will still be out about 7500 miles. With our only DI, I try to change the oil even sooner than the above. Basically syn buys me extra 2-3K miles.
 
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236
Location
Ohio
Generally yes, trust the olm. The GM system has been discussed here many times and it is generally agreed upon that it works well, and a sure bit better then mileage based in most scenarios. In a nutshell the olm will know how many times the engine turned over, how hard you were on the engine, if the engine was cold or warm or hot when you were hard on it, the idle time, the sustained engine temp, and how long it has been. It does NOT know however if you used cheap oil or the best oil ever. If you are under warranty always follow the olm, regardless of what oil you use. I believe you always have to use a dexos oil on that car too. Otherwise if you use the bare minimum, maybe change it at 20% life remaining, if you use a super premium best of the best oil, then maybe 3%. If you want to be extra special to the engine, change it at 50%. And if you are out of warranty and want to run the oil as far as you can then reset it and run it down a second time, changing at 50% or whatever your analysis shows is best.
 
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401
Location
Winnipeg
I phoned GM when I bought my 2008 Chevy in 2010 to ask about the OLM. I was told, as is described above, that it does not matter what type of oil I use but under what circumstances the car is driven. I have used only Mobil 1 5W-30 and 0W-30, with a new filter with every change, so I'm in no rush to change it when the OLM, calibrated for 2008 dino engine oil, as I was told after more questioning, tells me I'm down to 0 per-cent oil-life remaining, usually after about 5,300 miles (not kilometres).
 
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1,570
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WA
No matter what the auto manufacturers or the olm say, I would not trust dino or syn-blend or syn or yet a better syn (full syn and/or extended) the same way ... Meaning when I use a good syn or a Full syn (definition of which is somewhat tbd), I would not be as worried pushing the limits of oci as I would be using a dino or a syn-blend. I would consider olm being more useful for non-bitogers.
 
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34,398
Location
NY
The OLM has no idea what's in the sump. I'd get a UOA at the end of your normal OCI and base my OCI's on that. I'm not a fan of the OLM and ignore mine. I posted a thread about mine and how useless it is just last week.
 
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3,931
Location
Decatur AL USA
I think a change at a given OLM percentage makes more sense than mileage. The OLM adjust for changes in driving conditions.where as a flat mileage change doesn't.
 
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3,931
Location
Decatur AL USA
Originally Posted by MHartfield
From some testing on my 2013 Ford Focus SE, where I had my mechanic not reset the OLM, there is no algorithm ... it's set to 9,500 miles.
. Since the maximum is 10,000 mi and it alerts you 5% early and 90% of vehicles will call for maximum how do you know that? You have only confirmed the maximum. To the best of my knowledge Ford has no 10,000 mi maximum OCI cars that are just counters. 2014 Mustang 5.0 Always tracks 10,000 mi on Street. After going through 3 sets of tires in 4 weeks at open track events does not track 10,000 mi 2018 F150 3.5EB Always tracks 10,000 unladen.. After 4,000 mi at 9.0 mpg (45% of avg) pulling enclosed car hauler does not track 10,000 mi. My conclusion is you haven't really stressed it so it's still defaulting to max. If I'm wrong and you say left it idling whenever you were not driving for the 10,000 mi or it's a Focus Spec Racer I concede.
 
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189
Location
Monroe, WA
I trust the OLMs more than I do various oil company claims. They assume you use an oil that meets the spec they list in the owner's manual. The cheapest oil that meets the spec should last the life of the OLM. You don't need an analysis to tell you that. An oil analysis is a useful diagnostic tool to catch coolant leaks, fuel problems or some other contaminant but I distrust their use for what people claim to use them for around here. Just use the right oil, and follow the GM OLM. Oils marketed as synthetic may or may not buy you extra protection. It is difficult to verify so people argue endlessly about specs that may or may not matter.
 
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34,398
Location
NY
Originally Posted by KevinP
I trust the OLMs more than I do various oil company claims. They assume you use an oil that meets the spec they list in the owner's manual. The cheapest oil that meets the spec should last the life of the OLM. You don't need an analysis to tell you that. An oil analysis is a useful diagnostic tool to catch coolant leaks, fuel problems or some other contaminant but I distrust their use for what people claim to use them for around here. Just use the right oil, and follow the GM OLM. Oils marketed as synthetic may or may not buy you extra protection. It is difficult to verify so people argue endlessly about specs that may or may not matter.
I respectfully disagree. Some can be trusted, mine can't and I'm sure there are others as well that can't be trusted. OLM issue I have UOAs proving it is inaccurate. I'd be lucky if I followed it, it would have me doing ridiculously short OCI's. I'm sure they can screw up and be overly optimistic as well perhaps causing excessive wear and engine damage over the long haul.
 
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