Analyzing OLM and comparing to TBN

[himemsys]

Our CR-V just hit 50% on the OLM. Here's an updated progress report:

This vehicle's OLM decrements in 10% intervals until it gets down to 20%. So If we look at the rows between 50% (bold) and 60% (bold) we can estimate that each week is using up about 2% of oil life during that time span. So the most accurate value in the Predicted@ column will be the initial (bold) value. We've driven 2475 miles and used 50% oil, so current estimates show we'll hit 0% oil life at 4950 miles, on or about 11/4/21. If we changed at 12 months, regardless of miles, at the current rate of 13.6 miles per day that would be at 24204 miles, one day after the predicted 0% oil life.

I know none of this is pure science, I'm just doing it for fun. I'll probably end up doing this experiment til around 20% and change the oil earlier in the fall before it gets too cold.

 

[Danh]

OP, keep in mind your OLM is also counting down the 12 month max OCI, which complicates your exercise. For example even with no use after 4 months it would show oil life remaining of 66.6%, which would be displayed as 70%.

 

[himemsys]

Lots of highway miles between 50% and 40% increased the predicted miles on this oil from 4950 to 5498. We got 824 miles in between 50% and 40%, while we only got 404 miles in between 60% and 50% on the OLM.

 

[Hall]

How are you calculating the "predicted" value ? I have a spreadsheet with miles, % remaining according to the OLM ('12 Civic), and have graphed the results. Then I added a trendline that "ends" at 0%. As you point out, Honda only shows 10% increments so I have to record the mileage at each 10% increment and then overwrite the miles as needed. At 128,145, it showed 80%, which I recorded. Somewhere between 128,145 and the current 128,445, it dropped to 70%. I plotted that and the 0% value reduced but once I overwrote 128,xxx with 128,445, it bumped the 0% back up. I have to eyeball the intersection but it's currently on track to go 8700 miles.

You are showing the same "increase" that I'm trying to describe (well, because it is just math). Each 60% mileage increment that goes up causes your predicted miles to go up.

 

[himemsys]

How are you calculating the "predicted" value ? I have a spreadsheet with miles, % remaining according to the OLM ('12 Civic), and have graphed the results. Then I added a trendline that "ends" at 0%. As you point out, Honda only shows 10% increments so I have to record the mileage at each 10% increment and then overwrite the miles as needed. At 128,145, it showed 80%, which I recorded. Somewhere between 128,145 and the current 128,445, it dropped to 70%. I plotted that and the 0% value reduced but once I overwrote 128,xxx with 128,445, it bumped the 0% back up. I have to eyeball the intersection but it's currently on track to go 8700 miles.

You are showing the same "increase" that I'm trying to describe (well, because it is just math). Each 60% mileage increment that goes up causes your predicted miles to go up.

I'm using the formula
=(100/(100-X1))*Y1

Where X is the Oil Life Remaining and Y is current miles on oil.

So right when my OLM hit 40%, there were 3299 miles on the oil.

(100/(100-40))*3299 = (100/60)*3299 = 1.67*3299 = 5498

This is only accurate *right* when the OLM hits the next value down from the previous. That's why I have the first 60, 50, and 40 in bold, to indicate that is the value I'm going with until I get to the next 10% down.

 

[himemsys]

More highway miles between 40% and 30% on the OLM. Went 860 miles between 40% and 30%. Based on 4159 miles to reach 30% on the OLM, it's predicting 5941 miles to 0%. My plan is to change the oil at 5000 miles, so this experiment will be coming to an end probably before we hit 20%. You can see how the increase in highway miles had an effect. At 60% we predicted 5178 miles to 0%; at 50%, 4950 miles; at 40% 5498 miles (the highway mile increase started the week of 5/8/21); and at 30% the predicted miles to 0% shot up to 5941 miles. Yes, the 12 month timer is also playing a role in this, as you can see our average miles per day is predicting 5930 miles at the end of 12 months.

 

[Hall]

You should plug in your formula for each of the X0% increments so it shows how the predicted numbers increases.

Also, based on your predicted values at 60, 50, 40, and 30% remaining, the predicted mileage is floating around 5400 miles in comparison to the final predicted value of 5941. It doesn't look like the 12-month "time-out" is influencing the numbers just yet.

 

[himemsys]

You should plug in your formula for each of the X0% increments so it shows how the predicted numbers increases.

Also, based on your predicted values at 60, 50, 40, and 30% remaining, the predicted mileage is floating around 5400 miles in comparison to the final predicted value of 5941. It doesn't look like the 12-month "time-out" is influencing the numbers just yet.

The OLM only changes at each 10%. The bolded values are the % and mileage when the OLM "rolled over" to the next 10% lower. In some cases, this happens mid-week so I throw an extra row into the spreadsheet (see 7/20/21). Normally I check the mileage on Sunday mornings to get a "through Saturday night" mileage.

 

[himemsys]

I ended up changing the oil on the CRV before it hit 20% on the OLM. I estimate if the CRV displayed in 1% increments, it would've been at about 22% with 4885 miles on the oil. The TBN on the UOA for that oil was 2.2:

Since I have the spreadsheet template already in place, I'm going to continue this experiment on the fresh oil I put in and will report back here periodically with updates.

 

[himemsys]

After my recent oil change, our CR-V just hit 90% on the OLM. It took 590 miles, which at this stage in the game predicts out to 5900 miles to 0%. We're averaging 23.6 miles per day on this run so far, which comes out to 8600 miles per year. I'm not sure our current rate of driving will continue as consistently for the rest of this OCI, so it will be interesting to see if the one year mileage and OLM start to converge more as time moves forward. The OLM @ -46 means that the OLM would theoretically be at -46% at 12 months/8614 miles.

 

[mightymousetech]

My Ford similarly “rewards” you for taking a long trip. Not only does it barely budge for the trip, but the meter slows to a crawl for a few days afterwards.

Honda’s system seems to be based more on number of cold starts (and ambient temp started at) than mileage driven. Have seen oil changes due anywhere from 3000 km to nearly 20,000 km.

 

[himemsys]

Yesterday we hit 80% on the OLM. This time, I actually saw it change from 90% to 80%. I usually catch it after the fact and estimate the mileage it occurred. So, for some reason, we got a lot more miles going from 90% to 80% even though I don't think our highway miles were significantly more than they were going from 100% to 90%. I could be wrong. We went 590 miles from 100 to 90, and 868 miles from 90 to 80. Overall, that averages out to a predicted 7290 miles til the OLM hits 0%. Of course, I know this will fluctuate a lot as we put more miles on this oil change.

I'm also tracking predicted miles per year to see if the OLM will become more in sync with miles per year the closer we approach one year. It is said, Honda's OLM will accelerate towards 0% as one approaches one year on the oil to make sure the oil is changed at 12 months regardless of what the OLM would otherwise say if that factor was removed. So at the moment, the OLM predicts 7290 miles to 0% while our mileage prediction for 12 months is currently at 9676.

Regardless, I plan on changing the oil out at 6000 miles, so we'll see how this all plays out when we hit that mark -- what the OLM will be at, and how close we got to 12 months on the oil. We are approaching winter, so as the weather gets closer to freezing, that should affect the OLM negatively, plus we'll probably be driving fewer miles the colder out it gets.

 

[UncleDave]

I ended up changing the oil on the CRV before it hit 20% on the OLM. I estimate if the CRV displayed in 1% increments, it would've been at about 22% with 4885 miles on the oil. The TBN on the UOA for that oil was 2.2:
View attachment 70735
Since I have the spreadsheet template already in place, I'm going to continue this experiment on the fresh oil I put in and will report back here periodically with updates.

As I predicted in March - at 6K you will have no TBN problem.

Curious are you following the A/B filter schedule?

 

[UncleDave]

I'm also tracking predicted miles per year to see if the OLM will become more in sync with miles per year the closer we approach one year. It is said, Honda's OLM will accelerate towards 0% as one approaches one year on the oil to make sure the oil is changed at 12 months regardless of what the OLM would otherwise say if that factor was removed. So at the moment, the OLM predicts 7290 miles to 0% while our mileage prediction for 12 months is currently at 9676.

Regardless, I plan on changing the oil out at 6000 miles, so we'll see how this all plays out when we hit that mark -- what the OLM will be at, and how close we got to 12 months on the oil. We are approaching winter, so as the weather gets closer to freezing, that should affect the OLM negatively, plus we'll probably be driving fewer miles the colder out it gets.

My 2017 Honda V6 oil life monitor has no calendar day dependencies or acceleration.

 

[himemsys]

As I predicted in March - at 6K you will have no TBN problem.

Curious are you following the A/B filter schedule?

Do you mean changing the oil filter every other time? No. I change it every time.

 

[himemsys]

My 2017 Honda V6 oil life monitor has no calendar day dependencies or acceleration.

I'm not certain my 2018 CR-V does, just going by what I've heard others say on these forums. It did seem on the last interval that the deeper into the oil life I got, the more the OLM seemed to be syncing up with a 12 month timer.

 

[UncleDave]

Do you mean changing the oil filter every other time? No. I change it every time.

Thanks, just wanted to know.

 

[himemsys]

I'm not certain my 2018 CR-V does, just going by what I've heard others say on these forums. It did seem on the last interval that the deeper into the oil life I got, the more the OLM seemed to be syncing up with a 12 month timer.

Funny, but I just hit 50% on the OLM a few days ago and numbers are almost exactly lining up for the OLM to hit 0% at 12 months.

3785 miles to hit 50% on OLM = 7570 miles to 0%
It took 185 days to reach 3785 miles.
3785 / 185 = 20.5 mi per day
20.5 * 365 = 7483 mi in a year

We happened to go for a long drive today, which put our mi/day average for this OCI to 20.8.
20.8 * 365 = 7574 mi in a year

 

[himemsys]

We had a 2500 mi road trip recently. I was curious how the OLM would react to it. I changed the oil and reset the OLM about 150 miles before we started. It took 662 miles for the OLM to hit 90% (including that initial 150 miles we drove prior to starting the roadtrip). Then it took 910 miles for the OLM to hit 80%, followed by a whopping 1265 miles for the OLM to hit 70% (by which point we had just finished our road trip). So the OLM is pretty conservative about slowing down when it detects almost all highway miles. I'm still going to change the oil at 5000 miles, and I estimate the OLM will be somewhere between 60% and 50%.