Do I Have a Problem: Oil Level Sensor?

[Incompatible]

07 3.0Si with 15,000 miles on the clock with the electronic oil level sensor; no apparent oil consumption problems. Had a dealer oil change for annual low mileage service about 3 months and 2000 miles ago. As a habit I always check oil level each time I use the car. I realize that with someone else performing the oil change, the actual oil level (a little over/exact/a little under) is unknown due to the characteristics of the electronic sensor. I did get a "full" readout after the oil change and for the last 2000 miles since.

On the way up to participate in the Tour de Orange on New Years Day (great event) the oil level readout indicated one increment low, so on my return I added 1/4 liter of 5-30 BMW oil. My expectation was that the readout should now indicate the level at full; the readout still indicates one increment low. Do I add more oil? Another 1/4 liter, less, more? Is this an idiosyncrasy of the sensor? Is the sensor not reading accurately? Any thoughts are appreciated. TIA

[BMWI6]

This is one reason I hate the electronic sensor. If it reads a quart low after using the car for a full day, then I would add half a quart and see what happens.

[vicj]

Or you could take it to the dealership for their high-tech oil measurement procedure. They dump out your oil, measure it, then pour the dirty oil right back in your car...out of the same container they had used for this procedure hundreds of times already. So you get your own dirty oil back, plus bits and particles of everyone else's. Cool! Gotta love BMW for fixing things that were never an issue.

[mhughett]

Originally Posted by Incompatible

07 3.0Si with 15,000 miles on the clock with the electronic oil level sensor; no apparent oil consumption problems. Had a dealer oil change for annual low mileage service about 3 months and 2000 miles ago. As a habit I always check oil level each time I use the car. I realize that with someone else performing the oil change, the actual oil level (a little over/exact/a little under) is unknown due to the characteristics of the electronic sensor. I did get a "full" readout after the oil change and for the last 2000 miles since.

On the way up to participate in the Tour de Orange on New Years Day (great event) the oil level readout indicated one increment low, so on my return I added 1/4 liter of 5-30 BMW oil. My expectation was that the readout should now indicate the level at full; the readout still indicates one increment low. Do I add more oil? Another 1/4 liter, less, more? Is this an idiosyncrasy of the sensor? Is the sensor not reading accurately? Any thoughts are appreciated. TIA

I have the same year and model as you do and I just looked in the owner's manual to confirm and it does not provide for amounts that your oil is low. According to the readout, the message can be one of the following:
1. Oil level OK
2. Oil level being checked
3. Oil level at minimum level, put one quart in.
4. Oil level too high
5. Oil level sensor defective.

Based on the manual, there are no provisions for 1/4 quart low, 1/2 quart low, etc. As long as you get the "OK" sign, I'd leave it alone. I certainly don't want my oil removed and then re-inserted back into my car.

[Incompatible]

Originally Posted by mhughett

...Based on the manual, there are no provisions for 1/4 quart low, 1/2 quart low, etc. As long as you get the "OK" sign, I'd leave it alone. I certainly don't want my oil removed and then re-inserted back into my car.

I may be wrong, but my understanding is that the increments on the readout (bars) indicate level in 1/4 quart quantity and as such, you can have an "OK" when at full (all bars reading), 1/4 quart down (1 bar down reading), 1/2 quart down (2 bars down reading) until you reach the add oil reading.

My primary concern is not being down 1/4 quart but having the sensor indicate 1/4 quart down and not showing any change after adding 1/4 quart.

[mhughett]

Originally Posted by Incompatible

I may be wrong, but my understanding is that the increments on the readout (bars) indicate level in 1/4 quart quantity and as such, you can have an "OK" when at full (all bars reading), 1/4 quart down (1 bar down reading), 1/2 quart down (2 bars down reading) until you reach the add oil reading.

My primary concern is not being down 1/4 quart but having the sensor indicate 1/4 quart down and not showing any change after adding 1/4 quart.

I don't think it has the ability to give you increments like this. I would not add any oil until your display tells you that you are a quart low. Remember, these cars hold 7 quarts when full and even if you have 6 quarts of oil in the crankcase, it will not harm the engine. However, do not add too much oil as this can cause other serious problems. Since BMW has deleted dipsticks and oil pressure gauges from their cars, they are telling us to not worry about it until they give us a signal that action must be taken. While I don't always agree with their maintenance recommendations (i.e. oil change intervals) in this case, I would follow their advice.

[Incompatible]

Quote:
Originally Posted by bten
If it does not indicate overfill, and still reads "OK", I would just leave it alone. I woud drive it for a day or so and check it again. It has been my experience that the sensor does not immediately react to a change. I had an overfill issue, and had them take out the oil and start over. It still said overfill, but the service guy told me to drive it for a couple of days, and the sensor would reset. He was correct.

Thanks for the post, the sensor does appear to have a response lag based on my additional developments. To recap: Return home from Tour de Orange drive with readout showing one division low, add 1/4 quart, car sits for several days. Drive to and from work, each way about 30 min drive time, sensor still reads one division low each way. Drive in to work today and sensor reads full.

It appears that this is a quirk/aspect of the oil pressure monitoring design. Possibly a long interval average to counter short interval variations from oil temp, cornering, road incline...? Thanks again for the post and for contributing to the forum.