They design them based on the type of oil they specify, I'll bet, so if your car only calls for conventional and you use a blend or full synthetic, you'll have PLENTY of cushion (time or mileage).
what does a car computer use to compute oil life remaining?
- Thread starter BrianApp
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A few people have looked at Ford's "values" and made some educated guesses. They have seen things like this:
- For a huge % of drivers, their driving style is NOT considered severe so they will typically track for 10k miles OR 12 months
- While tracking mileage vs months, they can see a linear drop towards 0% until ~9 months IF their mileage is very low. In those cases, the system adjusts and starts tracking based on 12 months as it sees it's unlikely to reach 10k before 12 months.
- Some drivers see 5k targets but they drive in dirty/dusty environments, idle a lot, pull heavy loads, etc
Aren’t most of these driving habits (gradual acceleration, sustained highway driving at posted speed limits) said to increase OCI also driving habits thought to decrease fuel consumption? My 2007 Accords appear to have no noticeable time influence on OCI, which jibes with sentiment that “the oil doesn’t know how old it is”.
I strongly suspect that passenger car OLMs have OCI tied mostly (maybe close to 90%), but not entirely, to fuel consumption (more fuel, more heat, more chance for fuel dilution, more chance for production of other oil contaminants). Stated differently, even if car manufacturers have all kinds of other factors in their algorithm, I’d be surprised to find these other factors influence OCI more than 10% and that fuel consumption is by far the overriding factor in their algorithms.
I strongly suspect that passenger car OLMs have OCI tied mostly (maybe close to 90%), but not entirely, to fuel consumption (more fuel, more heat, more chance for fuel dilution, more chance for production of other oil contaminants). Stated differently, even if car manufacturers have all kinds of other factors in their algorithm, I’d be surprised to find these other factors influence OCI more than 10% and that fuel consumption is by far the overriding factor in their algorithms.
Those other factors may only apply weighted value in the total computation. Something like mileage has the most influence, RPMs next, idle time next, and so on. In the end, who knows.
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My 2002 Tahoe asks me to change the oil at about 4,300 to 4,600 miles. It has larger tires than factory with an uncorrected computer so the mileage counter is a bit slower. When the mileage on the dash counts 5,000 it's more like ~4,930 actual miles, if I did the math right. Not a huge difference.
My 2014 Silverado seemed to always settle right at about 7500 miles no matter what. Weird, cuz that's Chevy's own interval. Hmm.
My 2019 Jetta is obvious in how it works. Either you hit 1-year or 10,000 miles... end of debate.
My 2014 Silverado seemed to always settle right at about 7500 miles no matter what. Weird, cuz that's Chevy's own interval. Hmm.
My 2019 Jetta is obvious in how it works. Either you hit 1-year or 10,000 miles... end of debate.
Our 2018 CRV uses some algorithm based on driving style and does not appeared to be tied to any specific mileage or time interval (though I know Honda specifies 12 months as max). Our first three oil changes were all done with the OLM between 10% and 0% remaining:
1st: 6174 miles at 5.25 months (balanced mix of short trips and highway driving)
2nd: 8055 miles at 6 months (3000 mi road trip here)
3rd: 5011 miles at 11 months (mostly short trips)
Currently, our 4th oil is at ~2100 miles in 5 months and the OLM monitor says 60% oil life remaining. At the current rate, our 4th oil will get changed at 12 months with ~5200 miles on oil and approximately 20% remaining on the OLM. I'm curious to see how that actually pans out when 12 months comes up.
1st: 6174 miles at 5.25 months (balanced mix of short trips and highway driving)
2nd: 8055 miles at 6 months (3000 mi road trip here)
3rd: 5011 miles at 11 months (mostly short trips)
Currently, our 4th oil is at ~2100 miles in 5 months and the OLM monitor says 60% oil life remaining. At the current rate, our 4th oil will get changed at 12 months with ~5200 miles on oil and approximately 20% remaining on the OLM. I'm curious to see how that actually pans out when 12 months comes up.
Do they measure pressure drop across the engine air filter to determine this? I noticed my new Chevy has an engine air filter life monitor similar to the oil life monitor on the info screen.
This I like, it would not only tell you if the filter was getting too restrictive but if an aftermarket filter was too restrictive from the start or even if it was not restrictive enough (holes). I dont need a life monitor but value with high and low limits. If its just another mileage counter I can do that.
Just curious, at 10,000 mile OCI's what was the iOLM reading for oil life left. We have a 2017 Explorer with the 2.3 EcoBoost and when my wife was still working and commuting it was heading to 0% life at 10,000 miles all the time. Since it's an EcoBoost I usually changed it in the 6,500 to 8,000 mile range based on convenience. She retired the end of this past November and the iOLM is dropping faster with less miles driven. We use Mobil 1 5W-30, either the "vanilla flavor" or the EP, which ever I can get for less, both have performed well in the UOA's I've gotten and posted.I ignore the OLM in my 2017 Fusion. I just change the oil like I always have. Every 10K regardless of time.
We have a Fusion w/ Ecoboost and generally speaking, the OLM does target ~10k mile oil changes but it's not simply a 10000-0 mile counter. I've also graphed the % vs miles and with ours, based on our driving habits, it can vary from 8k to 10k miles where it is likely to hit 0%.
In the case of your wife's Explorer, if the OLM was tracking 10k miles = 0%, the computer considers her driving conditions to be easy-peasy (not "severe") so I think 7500-8000 miles is perfectly safe for her vehicle. Ford doesn't spec synthetic or even synthetic blended oil so they are okay with conventional running towards 10k miles. You're using synthetic so you've got that extra safety cushion.
In the case of your wife's Explorer, if the OLM was tracking 10k miles = 0%, the computer considers her driving conditions to be easy-peasy (not "severe") so I think 7500-8000 miles is perfectly safe for her vehicle. Ford doesn't spec synthetic or even synthetic blended oil so they are okay with conventional running towards 10k miles. You're using synthetic so you've got that extra safety cushion.
I have no idea since I don't re-set it at my oc. I just 0 it out when ever it comes on.
BMW uses various inputs, including fuel consumption. I never went according to it, but last yearI realized that tracking vehicle doesn’t influence OLM at all. Considering I was reaching several time 300f oil temperature, I was expecting OLM will drop faster, but nope.
It should drop faster because you're burning more fuel while tracking, but it's probably not significant enough to make a huge difference.
Older models, like mine, used fuel consumption only to determine OCI. In newer models like yours, fuel consumption is just one of many parameters, so it doesn't make that much difference I suppose.
Yes, in E90 it uses various parameters, fuel being one of it. It is definitely not based on oil condition itself.
I agree with you, I go by miles knowing what oil I have used, seeing UOA on the engine, and also after rebuilding enough engines.I ignore the OLM in my 2017 Fusion. I just change the oil like I always have. Every 10K regardless of time.
my olm......push trip a or b watch mileage reach a set point change oil/filter
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