What are Oil Life Monitors Based Upon ?

[Idrinkmotoroil]

Just curious what determines the results of oil life monitors, is it basically an engine revolution counter ?. The one in my 06 Honda Civic seems to change by 10% increments lately by the appearance of things. It doesn't move for weeks then all of a sudden drops by 10% one day. I'm near 5,000 kms and it is reading 60% right now. It probably isn't sophisticated enough to account for weather conditions or oil temps because I do a lot of short trips and it has been all in cold weather since December.

 

[Leonardo629]

I have the same car, and they are base upon engine revolutions and not mileage...

 

[Schmoe]

It's a computer program. It takes into account the rpm, miles, temperature, how long it idles, speed, etc. etc. Each company has their own version.

 

[martyi]

I have a Honda Ridgeline and the OLM has proven very accurate as a gauge for OCIs (according to UOA reports). Do a search on a a thread called "ZDP depletion and GM oil life monitor". It will contain posts from a GM engineer that I believe helped design their OLM. He explains it very well. I have to assume the Honda OLM is similar.

 

[Audi Junkie]

ftr- Mercedes' has an optical sensor.

 

[ARB1977]

If someone cant go by milage to change oil then they shouldnt be driving. No matter how many idot sensors they put in automobles someone will manage to mess something up.

 

[GoldenRod]

I have an OLM on my car too. I reset it to 100% during my oil change just so the warning doesn't come on half way through the OCI and bug me. Other than that, I don't pay any attention to it.

 

[rshaw125]

The OLM on my 03 Explorer has to be reset at around 5500 miles during a Mobil 1 EP oil life.Then I reset it again when I change the oil at 10,000 miles.

 

[thooks]

" If someone cant go by milage to change oil then they shouldnt be driving. No matter how many idot sensors they put in automobles someone will manage to mess something up. " What about police cars idling for 4+ hours a day? Fire/rescue vehicles running full blast for 3 minutes, then idling for 2-1/2 hours? What about tow trucks towing 8900 lbs for 30 miles, then nothing for 40 miles, then idling at the Waffle House for 45 minutes? What about the pizza delivery driver working 6 nights a week? What about the lil old lady that drives to church on Sunday, Grocery store on Thursday and the beauty shop on Friday, for a total of 28 miles?

 

[robbobster]

Mercedes-Benz has a setup similar to GM's for some cars. From http://www.practicingoilanalysis.com/article_detail.asp?articleid=562&relatedbookgroup=OilAnalysis DaimlerChrysler Corporation Flexible Service System DaimlerChrysler’s version of the oil monitor is called ASSYST in Europe and the Flexible Service System (FSS) in the United States. Like GM’s sensor, the FFS uses a computerized system to track multiple engine operating conditions. From research on oil quality through the span of an engine’s life, Daimler discovered that the breakdown in oil is determined by such factors as driving habits (frequent short trips vs. long trips), driving speed and failure to replenish low oil levels. Therefore, the FSS monitors time between oil changes, vehicle speed, coolant temperature, load signal, engine rpm, engine oil temperature and engine oil level. It uses this information to determine the remaining time and mileage before the next oil change and it displays the information in the vehicle’s instrument cluster. In addition, Daimler discovered that oil degradation is correlated directly with its ability to conduct electric current. Therefore, Daimler has fitted V-6 and V-8 engines with a digital oil quality dielectric sensor, that is mounted above the oil pan along with an analog oil level sensor. This sensor measures changes in capacitance, which effectively is a proxy for the amount and type of contaminants and oil degradation products present in the oil. An increase in dielectric constant (less resistance to electrical flow) indicates oil contamination and degradation. Daimler-Benz (Mercedes-Benz) has been incorporating the sensor into its vehicles since 1998.

 

[Jimbo]

So the dielectric sensor is in production cars. It makes sense because water and carbon (soot) both insulate less than pure oil.

 

[TomJones76]

The GM one takes load and temperature into account. Any driving you do will fit into one of four categories. It will penalize you for cold starts, stop and go driving, etc... anything besides highway cruising.

 

[joatmon]

BMW is based on fuel consumption. Two of mine were set at 3250 liters of gasoline. When reset, it showed the 3250 liters and works its way down to 0. Jack

 

[Mitch Alsup]

"If someone cant go by milage to change oil then they shouldnt be driving." I disagree, the application is critically important. Take, for example, a car that sees race trck use (high RPMs and oil temps in the 280dF range. After 200 miles of this kind of (ab)use, the oil is done. Same car, but operated on the interstates driving at constant 65-70 MPH, the very same oil can go for 15,000 miles. Same car, but this time operated for short trips in the city in cold weather, and the oil can only go for 7500 miles. So milage has to be considered with respect to the duty involved. "No matter how many idot sensors they put in automobles someone will manage to mess something up." Perhaps we should actually try to educate the people of this country.....

 

[Jimbo]

The Delphi monitor works by the dielectric constant (essentially electrical conductivity) of oil in the pan. I am not aware of any production cars that actually use this device. Older BMW's used revolutions with a "penalty factor" of double for operation below normal temperature or above 4000rpm. TRDUSA2002, Mileage is not the "holy grail" of oil life and that is the point of these systems. Toyota put in a simple light that is based only on "change it every 5000 miles", no mater what, but the owners manual at least adds the "or six months".

 

[Islandvic]

GM uses algorithms based on multiple inputs.

 

[Ken2]

I've seen a bell-shaped graph representing the GM oil life monitor. The left low mileage part of the graph is for short, cool trips...more frequent oil changes required. The center high mileage part of the graph is for long easy trips. The right side low mileage part of the graph is for heavy, hot trips...towing a trailer, etc. Ken

 

[TomJones76]

Ken2: If that chart was on-line anywhere, I'd appreciate a link.

 

[radiometer]

Idrinkmotoroil, As you've noticed your OLM counts down by tens in your 06 Honda Civic. From 100% oil life remaining it dropped to 90%, then to 80%. From 20% it drops at 5 percentage increments. So, when you see 60% oil life remaining you are somewhere between 50% and 60%. And so on.......... ..

 

[ARB1977]

Mitch No one in their right mind will run an oil after hard abuse lets say on the track abuse and go the distance for an oil change. If they have any brains you need to change the oil. The harder you drive the more often you change your oil. Thats my oil change monitor.