E92 M3 Minimum Oil Level Warning. Help?

[Alecb0929]

I was on a 4 hour roadtrip from my home in Orlando to where I go to school in Tallahassee when the oil level indicator seemed to drop below half, then about 20 minutes later again to minimum where it recommended I add a quart. I pulled over, restarted the car and waited to find the oil level sensor indicating it was 3/4 full. I drove on the highway for about another 20 minutes and the same issue reoccurred, so I pulled over once again and added half a quart. Once the oil level was fully read after about another 20 minutes of highway driving it indicated half full. I was able to make it the remaining 100 miles without the same error but the level is now indicating below half.

Could anyone help me diagnose this? The car just passed 66,000 miles and has no obvious leaks or oil burn symptoms that would equate to oil loss of this magnitude. Also, the oil was just changed about 1k miles ago.

[Redd]

Almost certainly oil level sensor then...

[Scharbag]

^^^

Yup - your sensor is likely giving up the ghost. Get a new one from FCP and change it the next time you change your oil. It takes about 5 minutes to change (BMW actually seemed to put some thought into its location and access).

And if you do not want to wait, and you do not want to spend more money on oil, just capture your oil in a CLEAN catch can and dump it back into the engine. I have done this many times. To ensure I do not dump anything bad into my engine, I also put a disposable paint strainer in the funnel when dumping the captured oil back into the car.

Cheers,

[Alecb0929]

After having the car for a couple days and going through some heat cycles, I'm getting consistent readings of the oil at the maximum level within operating range. I plan to replace the sensor but do you think this should be cause for concern in the meantime? The last thing I need is overfill.

[Helmsman]

Some S65s consume a liter oil per 1500 miles (the ost extreme I've read about thoug), some consume close to nothing. As your sump was filled up recently, work your way back and see if 1.5 liter seems within reason. If not, I'd personally start all over by dumping the oil and refill to avoid over fill.

This bloody sensor... mine has treated me ok during my 6 years but I have experienced very strange behavor after oil change, such as showing decrease after top up...

[Space Fox]

Mine was acting up after my last oil change. Initially overfilled warning, took out a liter, underfilled, added back half liter, underfilled, etc. etc. Kept reading underfilled and freaking me out so I spent the money for a new sensor, drained the oil in to a clean pan, measured out, replaced the sensor, dumped the oil back in and she's good to go. Sucks these cars don't have dipsticks but it's worth the couple hundred dollars for peace of mind knowing you have the correct amount of oil. That was also the first and last time I have someone else change the oil on my car.

[Alecb0929]

Originally Posted by Helmsman

Some S65s consume a liter oil per 1500 miles (the ost extreme I've read about thoug), some consume close to nothing. As your sump was filled up recently, work your way back and see if 1.5 liter seems within reason. If not, I'd personally start all over by dumping the oil and refill to avoid over fill.

This bloody sensor... mine has treated me ok during my 6 years but I have experienced very strange behavor after oil change, such as showing decrease after top up...

Just as an update, I had the sensor replaced with a fresh oil change. For the past couple months, this seemed to solve the issue as the level indicated 3/4 for nearly 1k miles since the change. Then, today I went for a 20 min highway drive and did a quick pull up to about 100 mph. Not even 5 minutes later the sensor said "+1 quart". I pulled over after 5 minutes and shut the car off, gave it a couple minutes and restarted, level indicating 3/4 again. Just as last time, no oil smell or fresh leaks in the engine bay. Should I be worried now?

[Helmsman]

Originally Posted by Alecb0929

Just as an update, I had the sensor replaced with a fresh oil change. For the past couple months, this seemed to solve the issue as the level indicated 3/4 for nearly 1k miles since the change. Then, today I went for a 20 min highway drive and did a quick pull up to about 100 mph. Not even 5 minutes later the sensor said "+1 quart". I pulled over after 5 minutes and shut the car off, gave it a couple minutes and restarted, level indicating 3/4 again. Just as last time, no oil smell or fresh leaks in the engine bay. Should I be worried now?

Always irritating when everything isn't perfect but realisticly I can't see reason for you to loose sleep over it. I'd certainly keep a close eye on the oil - which I do everyday anyhow - but one must assume that the sensor shout at you should the level drop dangerously low. At 3/4 you should in theory be able to ad at least 0.25L without overfill if you want to play around with sensor reactions (easy enough to take some out via the fill) but I'd run for a while first and see what happens.

[Alecb0929]

Originally Posted by Helmsman

Always irritating when everything isn't perfect but realisticly I can't see reason for you to loose sleep over it. I'd certainly keep a close eye on the oil - which I do everyday anyhow - but one must assume that the sensor shout at you should the level drop dangerously low. At 3/4 you should in theory be able to ad at least 0.25L without overfill if you want to play around with sensor reactions (easy enough to take some out via the fill) but I'd run for a while first and see what happens.

Yeah I'm just gonna go with it for now, the oil level read 3/4 for the rest of the drive back even after being recalibrated. That being said, it is kind of frustrating not knowing what exactly is going on. When it did throw the low oil warning it happened suddenly and there wasn't a linear decline in oil level, but then like nothing its back to normal again after the car restarts. Hopefully its nothing mechanical, given how much of a problem the rod bearings are oiling problems would only worsen that. Thanks for the advice.

[Daniel_92m3]

Originally Posted by Alecb0929

Yeah I'm just gonna go with it for now, the oil level read 3/4 for the rest of the drive back even after being recalibrated. That being said, it is kind of frustrating not knowing what exactly is going on. When it did throw the low oil warning it happened suddenly and there wasn't a linear decline in oil level, but then like nothing its back to normal again after the car restarts. Hopefully its nothing mechanical, given how much of a problem the rod bearings are oiling problems would only worsen that. Thanks for the advice.

I am having similar problems, only that after the oil drops on the highway , i stop, restart and oil sensor just wont read for half an hour or so.

Have you find any solution?

Thanks

[Alecb0929]

Originally Posted by Daniel_92m3

I am having similar problems, only that after the oil drops on the highway , i stop, restart and oil sensor just wont read for half an hour or so.

Have you find any solution?

Thanks

After replacing the oil level sensor didn't work, I went with the dumb route and had a dipstick put in during the rod bearing service lol. However, the shop I had it done at said they thought it was likely the wiring harness connecting to the sensor that was causing the inconsistencies.

So, I'd try the sensor and the wiring harness connection first if the issue persists.

[eroobeeroo]

Definitely seems like the sensor. They start to go crazy like that. Replace sensor and add proper amount of oil and see if issue is fixed

[Daniel_92m3]

Originally Posted by Alecb0929

After replacing the oil level sensor didn't work, I went with the dumb route and had a dipstick put in during the rod bearing service lol. However, the shop I had it done at said they thought it was likely the wiring harness connecting to the sensor that was causing the inconsistencies.

So, I'd try the sensor and the wiring harness connection first if the issue persists.

Sensor changed, but problem is the same.

So we will try the wiring harness connection next.

Thanks for the hint

[drrust]

I experienced similar issues. After replacing the oil separators between the plenum and valve covers it serotonin be a bit better. I would say I still get flaky oil sensor readings though.

[NeverL8]

Originally Posted by Space Fox

Mine was acting up after my last oil change. Initially overfilled warning, took out a liter, underfilled, added back half liter, underfilled, etc. etc. Kept reading underfilled and freaking me out so I spent the money for a new sensor, drained the oil in to a clean pan, measured out, replaced the sensor, dumped the oil back in and she's good to go. Sucks these cars don't have dipsticks but it's worth the couple hundred dollars for peace of mind knowing you have the correct amount of oil. That was also the first and last time I have someone else change the oil on my car.

How’s the sensor holding up? Did you have to take off skid cover plate to access the sensor?

[Space Fox]

Originally Posted by TheRussski

How’s the sensor holding up? Did you have to take off skid cover plate to access the sensor?

All good on my end - I had to loosen the bolts to wiggle it out but did not have to remove it entirely.