# Engine oil life indicator



## Jim Frye (Mar 16, 2011)

I'm pretty sure the OLM algorithms in cars do not understand what sort of oil is in the crankcase. I run Mobil1 0W-20 in my car and it always hits 15% at about 6,500 miles, same as the factory fill. We do mostly city driving and that should shorten the calculated life span of the oil. The computer calculates Oil Life based on rpm, mileage, temperatures, and a few other inputs. Oil brand or base are not in the calculations. Neither is the chemical state of the oil during the Oil Life span.


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## jsusanka (Jan 31, 2011)

yes it should. a better oil will take longer to break down. but the olm doesn't know the kind of quality oil you use. it works like everyone else says using calculations on all sorts of variables. good oil will take longer to break down.


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## Robby (Mar 1, 2013)

It uses a combination of factors......none of which has anything to do with the oil being used.

Time: 0% at one year intervals.
Mileage: 7500= 0% (I think)
Start and run cycles....the criteria is not printed per se but short trips make for a faster percentage dropoff......long drives at full temperature will generally show declining percentage in line with miles since last reset.

Rob


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## spacedout (Dec 7, 2010)

Robby said:


> Mileage: 7500= 0% (I think)


2011-2012 will go allot farther than that on the OLM, mine typically would take me 10,000+ miles if I followed it. Since getting the emissions recall done to my car in May of 2015, the 7500 miles seems accurate. It now seems to drop at 2X the rate it used to.


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## Tomko (Jun 1, 2013)

Some engines have sensors to detect engine oil quality. I believe Mercedes uses a light shining through the oil to detect opacity. But to the best of my knowledge GM uses only algorithms on its engines based on the factory fill requirements.


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## Hazlitt777 (Nov 2, 2013)

Well, I plan on changing it at 7500. This is the first time I ran this oil rather than the factory GM blend...so maybe I should change it at 6000, to make sure I get all the old stuff out. After that, I think I will stick with changing it every 7500. 

Since most of my driving is highway I figure that the OLM may take longer than 7500 miles to run down. 

Thanks for the input. But it seems there are two schools of thought here...one that the oil used has an effect, the other that it doesn't.


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## Jim Frye (Mar 16, 2011)

Better oil will last longer, but the OLM won't know. I've run Mobil1 in my engines since 1980 on a 10,000 mile Oil Change Interval with absolutely no issues on any motor. Current Mazda Protege5 is at 94K miles on the 10K OCI and the engine uses no oil in that period. I'm following the computer on the '13 Civic for warranty reasons, but I'm going to continue to change it when it hits 15% as SWMBO hates the computer nagging every time the engine is started by displaying a message on the iMID screen.


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## spacedout (Dec 7, 2010)

Hazlitt777 said:


> Thanks for the input. But it seems there are two schools of thought here...one that the oil used has an effect, the other that it doesn't.


The OLM is all based on a GM priority algorithm which takes many variables into the OLM calculation like Robby said above, There is no sensor or anything like that that can tell what type of oil you are using. You could fill the car with drain oil(not recommended) and reset the OLM, it would take you the same 7500 miles+ until the next time I would tell you to change it. 

I drive about 70% highway and change my oil with mobil 1 every 6000-7500 miles. In the winter months when I do more idling I change it much sooner(3000-5000 miles). No matter what mileage, I change my oil a minimum of 3 times a year. For me that would be spring, summer and fall, that way I have fresh oil after all the winter idling, before the heat of the summer(when I put on the most miles) and in the fall before the winter cold sets in.


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## XtremeRevolution (Jan 19, 2012)

The oil used does affect what condition the oil will be in when changed. I simply reset my oil life monitor and change my filter at 7500 miles, going 15,000 miles between changes using AMSOIL'S signature series oil. 

The vehicle doesn't know what oil I'm using and would run down the oil life monitor just the same with semi synthetic. 

GM did recalibrate the oil life monitor algorithm for 2013+ models, which significantly reduced the service interval of the engine oil. They also redesigned the turbo oil feed line as it was coking up from the cheap oil used being exposed to high temps while the engine was off and starving the turbo of oil. 

I strongly recommend everyone run a synthetic oil of some kind in the 1.4T.


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## Alex V. (Sep 20, 2013)

I've noticed the OLM on my '13 drop at seemingly different rates depending on what kind of driving I'd done more of in the recent past (slowest when most of my driving was fairly steady 50-65 MPH on fairly flat 2-lane roads), but I've never used it as an aid in calculating my OCI. I'm with the majority, that it is more complex than just a counter run off the odometer, but it can't know if it's judging Dexos1 syn. blend or a superlube like Amsoil. Examining the engine's construction, oil capacity vs. displacement, personal driving environment, etc., I made my own decision and after two shorter intervals using up my free changes from the dealership settled on Valvoline full synthetic @ 5,000 mi. OCI, which at 50,000 miles I extended to 7,500 miles with a change to Schaeffer's full syn. and I'm 2,500 miles away from draining that out right now. No piston slap, no oil consumption, above average fuel economy and no unexpected dealership visits that it seems so many owners are plagued by lately.


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