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-   -   Oil Life Monitor (https://www.bimmerfest.com/forums/showthread.php?t=1330351)

chris.luurtsema 05-14-2019 03:57 PM

Oil Life Monitor
 
Hello! I have a 2014 328xi N26 w/ 68k miles. I changed my oil about a month ago and reset the oil life monitor afterwards. I used BMW Twin Power oil and Mann filter from FCP euro as I have done for the last two oil changes since my 50k service program dried up.

My question is in regards to the oil life monitor and how quickly it updates. I keep noticing during startup that the next service is in 9000 miles.
(oil is the next service due in the menu list this followed by a service check in 27k)

I have put about 1300 miles on the car since the oil change and the monitor has not reflected a change from the 9000 initial count down. Is this normal? I do a lot of highway miles but my OCI has averaged about 8500 miles according the CBS monitor. I am wondering if the computer is messed up or has a glitch? I thought it showed a countdown quicker.

I appreciate any input.


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chris.luurtsema 05-15-2019 10:01 AM

Bueller.... Bueller...[emoji3]


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Wolfus Aurelius 05-15-2019 12:46 PM

If you're doing mostly highway miles, that's the easiest kind of mileage for any car. That kind of service has barely tapped the ability of the oil to lubricate, cool, and hold contaminants in suspension. I suppose you might see a change soon, but 1300 highway miles out of a projected 9000 OCI is not very stressful at all.

Which reminds me to ask: How does BMW's computer figure the OCI? Is it by algorithm based on cold starts, city vs. highway driving, temps during short trips, etc. -- or does it actually test the oil?

namelessman 05-15-2019 01:50 PM

To OP, the CBS oil change interval is based on gallons consumed as well as oil condition read by the oil level sensor.

For F30 with OCI of 1 year/10000 miles, the number of gallons per OCI is around 333 gallons, assuming 30mpg.

If your mpg is above, or below 30mpg, the OCI miles will adjust accordingly.

chris.luurtsema 05-16-2019 12:09 PM

Thanks for the input. I will keep watching. I have been averaging just over 30 mpg. So that may be part of it.

I could just drive flogging the crap out of it to see if that changes anything as well..[emoji3]


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DCWhybrew 05-16-2019 09:18 PM

Its normal. Donít worry about it. The computer will let you know when to change the oil.


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John MS 05-17-2019 04:16 AM

I do a lot of highway driving too. The interval on mine actually ranges between 10k and 11k. It's been consistent since new. The highway mpg on my car is pretty impressive too.

Dave 20T 05-20-2019 09:51 PM

Quote:

Originally Posted by chris.luurtsema (Post 13000467)
I keep noticing during startup that the next service is in 9000 miles.
(oil is the next service due in the menu list this followed by a service check in 27k)

I have put about 1300 miles on the car since the oil change and the monitor has not reflected a change from the 9000 initial count down. Is this normal?

It is normal. What seems to happen is that it stays at a high number, say 9000 miles, for a long time. Then it drops to 8000 miles or so. When it is around 2000 miles, it drops like a rock.

In other words, slow countdown at first, then speeds up too fast.

Quote:

Originally Posted by Wolfus Aurelius (Post 13001525)
Which reminds me to ask: How does BMW's computer figure the OCI? Is it by algorithm based on cold starts, city vs. highway driving, temps during short trips, etc. -- or does it actually test the oil?

There is no chemistry lab in the engine compartment. It's not even resistance to electrical current or how well a float floats up.

I believe, but am not certain, that after 2000 liters of gas (about 500 gallons) is used, the oil life monitor indicates it's time to change oil. So a lot of cold weather, short trips will use up gas and result in a lower oil change interval. A moderate temperature and 100% long highway trips will have good fuel economy and a long oil change interval to 500 gallons.

Zeichen311 05-20-2019 10:43 PM

Quote:

Originally Posted by Dave 20T (Post 13006453)
There is no chemistry lab in the engine compartment. It's not even resistance to electrical current or how well a float floats up.

Correct - it's a capacitive measurement of the dielectric property of the oil. The oil condition/level sensor is based on a capacitor that uses the engine oil as the dielectric. As the oil ages the measured capacitance changes. In other words, direct measurement of oil quality is a variable in the CBS oil-service estimate. Fuel consumption is another and elapsed time since the last oil change (i.e., CBS service reset) is a third.

namelessman 05-21-2019 01:58 AM

Quote:

Originally Posted by Dave 20T (Post 13006453)
I believe, but am not certain, that after 2000 liters of gas (about 500 gallons) is used, the oil life monitor indicates it's time to change oil. So a lot of cold weather, short trips will use up gas and result in a lower oil change interval. A moderate temperature and 100% long highway trips will have good fuel economy and a long oil change interval to 500 gallons.

Yes that is what my bookkeeping shows, for 15000 miles/2 years OCI, the number of gallons consumed is set to 500 gallons for F30, assuming around 30mpg. The 10000 miles/1 year should be around 333 gallons.

Elk 05-21-2019 12:24 PM

Quote:

Originally Posted by Dave 20T (Post 13006453)
In other words, slow countdown at first, then speeds up too fast.

Akin to the fuel gauge.


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