Oil Level Sensor Inconsistency

I've been getting some inconsistent readings from my oil level sensor over the past few days which have me a bit concerned.

Prior to taking the car away on a trip for the weekend it was reading at one notch below maximum (250ml below full), so I added a quarter of a litre to bring it up to max.

After driving the car, the level didn't go to max, but instead dropped to the half way mark (500ml below full). I chalked this up to the classic weirdness from these sensors and kept driving. Despite me forcing many re-checks with the BC button, the level remained at the half way mark all weekend until Sunday afternoon while I was driving home, when it began reading at the full level again.

Great I thought - the sensor has finally re-calibrated itself and now it's reading correctly.

Sadly, this was short lived, as the sensor has since gone back to reading at the half way mark.


I am pretty accustomed to the way these sensors behave as I also have an E63 M6, so I know their quirky behaviour, however this seems a bit more unusual than anything I've seen before.

The car has no codes and upon running a check on the sensor in ISTA the software says the sensor is ok and it reads out the oil level in mm with no issues.

Should I replace the sensor as a precaution (at BMW's outrageous price) or give it some time and see if it stabilises?

I did, a couple of years ago.

If you do repace the sensor, get the OEM one from ECS or Turner, do not put a Chinese rip off cheap on in it, not worth saving a few $100 to potentially grenade a big $ motor.

I wouldn’t change it just yet. Just keep an eye on things. There have been countless threads of people swapping to new sensors (including oem) with issues (usually faulty new sensors or misdiagnosed voltage issues from what I recall)

nick3753 wrote

I wouldn’t change it just yet. Just keep an eye on things. There have been countless threads of people swapping to new sensors (including oem) with issues (usually faulty new sensors or misdiagnosed voltage issues from what I recall)

Agree 100%, I wasn’t at all suggesting ‘throwing the parts cannon’ at it, sorry I should have been a bit more specific. If you have to replace the level sensor after further diagnosing, just don’t use a cheap Chinese rip of one.

Hopefully you get it sorted

as long as you know you put 9L then you put 9L.

but if you're going to replace the voltage reg, you might as well replace the entire alternator, then do the oil sensor. imo.

Probably a silly question but are your BC resets on level ground and stationary? I find that on the move my readings sometimes differ, take longer but if I park it for a few minutes at I idle and read I tend to get better results and much quicker. I too sometimes get contradictory readings after an oil change sometimes but most times the readings jive.

Scrippy wrote

Probably a silly question but are your BC resets on level ground and stationary? I find that on the move my readings sometimes differ, take longer but if I park it for a few minutes at I idle and read I tend to get better results and much quicker. I too sometimes get contradictory readings after an oil change sometimes but most times the readings jive.

I was getting the same reading both stationary (on level ground) and on the move, however it seems to have come right now and is reading max consistently.

What seems to have happened is that I added slightly too much or too little oil for it to climb up a rung or stay where it was at 75% full, and that's made it throw a hissy fit and read half full instead. No idea how or why, but that's the only thing I can think of.

The readings these things give do seem a bit haphazard at the best of times but I guess with age it gets worse.

Shall monitor it but I think it's ok for now.