Analyzing OLM and comparing to TBN

Messages
117
Location
Midwest
This will be an on-going experiment on our 2018 Honda CR-V 1.5. I will be tracking miles to each 10% on the OLM, then when we get to at or around 0%, will do an analysis and TBN. Just for fun and curiosity. Here's the data so far:

OLM.jpg


So as of today, based solely on assumed linear degradation (which I know is not how TBN works), the OLM should hit 0% at around 4800 miles of oil use on or around January 6 of 2022. Based on current low mileage mostly city driving of ~11 miles per day.

It will be interesting to see how the predicted results change at each 10% loss of oil life and how the actual TBN looks when I hit 0%.

This vehicle has had 3 oil changes in its lifetime and each one was done at between 0% and 10% remaining on the OLM:
First oil change at 6174 mi on oil in 5.25 months
Second oil change at 8055 mi on oil in 6 months (this trip included a 3000 mi round trip vacation drive)
Third oil change at 5011 mi on oil in 11 months (can you tell when the pandemic hit?)

Has anyone else done anything like this?
 
Messages
8,620
Location
Champlain/Hudson Valley
Great idea.
Can access this original post be arranged throughout the life of this experiment so you can just add numbers to the chart posted?

Also, looking at the OLM column, are 90% and 80% values not included on your OLM readout?
 

himemsys

Thread starter
Messages
117
Location
Midwest
Great idea.
Can access this original post be arranged throughout the life of this experiment so you can just add numbers to the chart posted?

Also, looking at the OLM column, are 90% and 80% values not included on your OLM readout?
I didn't come up with the idea til 70% :)

Yeah, I'll update this thread when I hit % markers. Not sure how this forum works -- if I'll be able to edit the original post months down the road, but if I can, I will.
 

himemsys

Thread starter
Messages
117
Location
Midwest
I'm going to say your oil is going to be fine from a TBN standpoint, but needing change from fuel/ oil fouling.
Yeah, I'm pretty sure our CRV has the fuel dilution problem (noticed high dipstick readings before last oil change) so I expect to see that on the UOA. I'm curious how that will affect wear metals -- hopefully not TOO much.
 
Messages
4,711
Location
Ca.
Yeah, I'm pretty sure our CRV has the fuel dilution problem (noticed high dipstick readings before last oil change) so I expect to see that on the UOA. I'm curious how that will affect wear metals -- hopefully not TOO much.

With a 6K dump, using synthetic oil Im going to say its going to be largely irrelevant.

Remember people drove poorly tuned carbureted vehicles that were far worse for decades and still got superb life.
 
Messages
5,329
Location
Ohio
Honda says change the oil every 12 months no matter the mileage. Your vehicle (or usage) probably isn't the best case.
 

jurko

Site Donor 2021
Messages
633
Location
Carson City
Interesting experiment.
Do you have TBN and TAN measurements of virgin oil you are testing?
I would take a sample halfway through at 50% OLM and have TAN and TBN analyzed.
This will give you idea what is the rate of acids accumulation inside the engine and the amount of potassium hydroxide to fight those acids.
TAN is better indicator of actual operating conditions of engine.
TBN is only indicator of how much additive remains.
 

himemsys

Thread starter
Messages
117
Location
Midwest
Honda says change the oil every 12 months no matter the mileage. Your vehicle (or usage) probably isn't the best case.
Good point. We can always intentionally put more miles on it towards the end if we think we might not hit 0% before 12 months. Either that or just end the experiment at 12 months regardless of OLM reading.

Interesting experiment.
Do you have TBN and TAN measurements of virgin oil you are testing?
I would take a sample halfway through at 50% OLM and have TAN and TBN analyzed.
This will give you idea what is the rate of acids accumulation inside the engine and the amount of potassium hydroxide to fight those acids.
TAN is better indicator of actual operating conditions of engine.
TBN is only indicator of how much additive remains.
It's not easy to take a sample on this vehicle without dumping the pan. The dipstick holder is pretty narrow. I couldn't fit a 1/4" tubing down it when I tried prior to last oil change. The oil in there now is from Honda, assuming their bulk 0W-20. No virgin numbers that I'm aware of.

If taking a sample was easier, I'd probably do as you suggest.
 
Messages
3,079
I like the initiative. Is there a virgin baseline you are beginning with? What is the TBN beginning value? I'd look into tracking TAN on an experiment like this as well.
 

jurko

Site Donor 2021
Messages
633
Location
Carson City
Good point. We can always intentionally put more miles on it towards the end if we think we might not hit 0% before 12 months. Either that or just end the experiment at 12 months regardless of OLM reading.


It's not easy to take a sample on this vehicle without dumping the pan. The dipstick holder is pretty narrow. I couldn't fit a 1/4" tubing down it when I tried prior to last oil change. The oil in there now is from Honda, assuming their bulk 0W-20. No virgin numbers that I'm aware of.

If taking a sample was easier, I'd probably do as you suggest.
Ask them for pint of that oil they put in and have it tested. Otherwise you'll have test results and nothing to compare it with.
 
Messages
24,129
Location
CA
I'm going to say your oil is going to be fine from a TBN standpoint, but needing change from fuel/ oil fouling.
Agreed. TBN is only one of the factors which can condemn the oil from a service life standpoint. Viscosity, contamination levels (e.g. fuel) and wear metals are other factors to consider. I posted a 10K UOA from this engine with AP 0W-20 and the TBN was fine.
 
Messages
1,850
Location
Southwest
When I ran my IOLM almost all the way down and tested I had a TBN of 4 —- and an acid number of 5. Other parameters also showed the oil about done.

I know TBN is non-linear blah blah blah, but I always wondered why the oil was keeping its powder dry.
 

himemsys

Thread starter
Messages
117
Location
Midwest
We just got back from a mini vacation which involved about 450 highway miles over 2 days. The OLM didn't budge from 70%, though I'm guessing it's much closer to 60% than 70% at this point. Since Honda's OLM only changes in 10% increments, this will probably be a common theme in each 10% range. Anyhow, here are the updated figures:
OLM1.png

So the predicted oil life has jumped considerably to 6627 mi. Once we hit 60% on the OLM, that number should jump back down to closer to 5000. I added the '[email protected]' column that will be a snapshot of the predicted oil life on that date.
 
Messages
1,850
Location
Southwest
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.
 

himemsys

Thread starter
Messages
117
Location
Midwest
Our vehicle's OLM just hit 60% so I thought I'd update this. In reality, because this OLM only drops in 10% increments, the OLM is actually closer to 69%. I've also fine-tuned the spreadsheet a bit.
View attachment 52532
I've read that with Hondas, once you hit 15% the OLM starts dropping in smaller increments. Not sure of the details, but I'll keep track this time around.

Basically, at this point it is predicted that if I drive to 0% on the OLM, it will take well over a year (470 days) and ~6700 miles. If I change at one year regardless of OLM, that should take me to ~5200 miles on the oil (based on current 14.2 mi/day avg).

You can see how skewed the [email protected] column is because the spreadsheet is using 60% when it's actually closer to 69%. So the moment before the OLM drops to the next 10% is when this data is most accurate.
 

himemsys

Thread starter
Messages
117
Location
Midwest
Our vehicle's OLM just hit 60% so I thought I'd update this. In reality, because this OLM only drops in 10% increments, the OLM is actually closer to 69%. I've also fine-tuned the spreadsheet a bit.
View attachment 52532
I've read that with Hondas, once you hit 15% the OLM starts dropping in smaller increments. Not sure of the details, but I'll keep track this time around.

Basically, at this point it is predicted that if I drive to 0% on the OLM, it will take well over a year (470 days) and ~6700 miles. If I change at one year regardless of OLM, that should take me to ~5200 miles on the oil (based on current 14.2 mi/day avg).

You can see how skewed the [email protected] column is because the spreadsheet is using 60% when it's actually closer to 69%. So the moment before the OLM drops to the next 10% is when this data is most accurate.
Something got borked with the spreadsheet attachment. Let's try again:
OLM040321.png
 
Top