Oil Level Sensor acting erraticly
 

I bought my 2007 530xi with 85000 miles on it a week ago and drove it from Chicago to Maine. everything worked perfectly until 3 days ago I got a message saying 'oil at minimum - add 1 qt' so I added a quart of oil and bought enough oil to store a few quarts in the trunk and also to do an oil change. The next morning I started the car, let it warm up in the driveway and checked the oil in the iDrive system and it said 'oil level OK' and showed it was just 1/4th above the low indicator. I started driving and 15 minutes later I got the alert that the oil was at minimum and to add a quart, so I added another quart when I arrived at work, the same thing happened on the way home so I added another quart.... last night I decided that I should drain the oil and see how much oil i'm missing and make sure it wasn't leaking from the drain plug. I removed the drain plug and not only did the 7 quarts the engine is supposed to have come out the additional 3 quarts of oil i added came out and made a huge mess on my garage floor (my oil drain pan only holds 7qts) so I changed the filter and added 7 quarts of oil.

This morning pulled out of the garage, made sure there was no oil on the floor, let the car warm up and verified the oil level was good in the iDrive system. Again I drove 15 minutes and I got a new message that my oil is below the minimum level, (it never even went from ok to minimum, just straight to below) and damage may occur, I carefully brought it back to my house. later in the afternoon I started the car and checked the iDrive and surprise... the oil level reported it was OK. I suspect that the oil level is fine and its just the oil level sensor (I have read they have problems in cold climates like here in Maine) but oil in an engine is not something I take chances with. If anyone has any ideas or can confirm this is the oil level sensor when its close to failure id really appreciate it as i'm stressing over a car I've owned for exactly a week wondering if I've made a terrible mistake.

I've been in (possibly still am) in a similar situation...in the same climate too: Boston <-> E. Boothbay
The oil sensor I have found to be finicky at best. After my oil pan was replaced at 119k miles, the shop left the original sensor in and it would go from a yellow iDrive alert to being "OK" all within a 50 mile drive. My point is if your oil pan has been replaced but not the sensor, that might be why its so inaccurate.

When mine was replaced with the OEM unit, the issue went away...somewhat. It will still occasionally deviate between 3 and 4 "green blocks" over 6k miles but it no longer indicates a dire warning when there isn't one. If your test revealed 7 quarts plus the additional 3, I would say you are safe but have a failing/failed sensor. A good flashlight will reveal any significant loss of oil. Autowerkes in Freeport has been knowledgeable and reasonable for my 2006 530xi wagon.

Not sure if this applies, but seem to recall reading that water (moisture) in the oil will throw off the sensor. Do you make many short mileage trips? If the car runs for an extended period of time, does the problem go away?

Thank you both for replying I think i'm in the same boat as TwoPedal, the sensor is just failing and I have ordered a new one. I typically drive 45 minutes to work, on occasion I have a short trip to bring my kid to daycare in the morning but right after that I drive to work and the sensor doesn't seem to show any better results the longer I drive.

congrats on your purchase, BTW! its a GREAT car!!

Thanks Razzy! I replaced the sensor this weekend and now its showing perfect at the Max level and it stayed there all the way to work today! I feel like I can finally relax and trust that the car is telling me the truth about its oil level.