[Mark e90]

I'm a little concerned / confused about my oil level.

The last I checked was around 200 miles ago and it was reading half full then tonight whilst driving I got the little exclamation mark and when I checked it was oil level add 1L. I pulled over after roughly 5 miles, I was a little concerned that it was telling me it was empty as i do monitor the consumption and its not usually as much as that ! I added around two thirds of the 1L top up bottle I have and drove home ( around another 5 miles ) the level now reads full !


Basically I'm now worried that there may be something wrong with the level reader. Tomorrow I will measure out how much is left in my top up bottle and report back with exactly how much I added. Will also have a good look around for any leaks.

I have found that the car burns 1 bar on the reading ( 250ml ) of oil per 300 miles. So the other thing I'm thinking that could have happened is when I last checked and it read half it may just have been ready to drop down to quarter ( last bar ) which is generally when I will top up, never had it low enough to tell me to add 1L before

[Mark e90]

Just measured out the remaining oil in my top up bottle and turns out I added just over half a litre. Was out in the car today for a decent run and it's consistently showing oil level at full ( 4 bars ).

As I said the last time I checked the oil before I got the warning it was at half way so I'm now thinking it may have been a false alarm telling me I need to add 1 litre. Glad I only added 500 ml now !

I am reasonably confident the the current reading is correct but I'm just wondering if it may be best to just dump the oil and change the oil level sensor as it looks like it may be going bad. Could just be a one off I suppose but it doesn't really sit well with me....

What do use recon ?

[Mboon]

Does yours have a dipstick?

I get odd readings from my dipstick at times and actuslly put a bit too much in mine. If you are relying just on the sensor, I don't personally trust them... but I know some of the E90s do not have a dipstick

[Mark e90]

yeah unfortunately mines has no dipstick

Don't get me started on that !

[Mark e90]

Anyone?

[Chappers 71]

Mark, the oil monitoring system is pretty clever as well as the amount of oil it also monitors its condition.
There's plenty of oil in the engine even if it's down a litre, if your not putting out blue smoke & have no obvious oil leaks everything should be fine.
I would suspect if something as important as the oil monitoring system had a issue it would give a warning & throw a code.

Also when checking oil the engine needs to be up to operating temp & obviously you need to be on a level surface

I've had my 35i for 5 years & have always added 1 litre when the system has asked for it & never had any issues It's now done 104k.
The intervals between topping up are dependent upon how you've been driving your car, the harder you drive the more oil you'll use.

Relax & let the system do its thing

[JIMT8292]

Daft question as only had mine 2 weeks - electric dipstick checking - engine running, tickover on flat ??

[Chappers 71]

Yep flat level surface & engine up to temperature

[Mark e90]

Originally Posted by Chappers 71

Mark, the oil monitoring system is pretty clever as well as the amount of oil it also monitors its condition.
There's plenty of oil in the engine even if it's down a litre, if your not putting out blue smoke & have no obvious oil leaks everything should be fine.
I would suspect if something as important as the oil monitoring system had a issue it would give a warning & throw a code.

Also when checking oil the engine needs to be up to operating temp & obviously you need to be on a level surface

I've had my 35i for 5 years & have always added 1 litre when the system has asked for it & never had any issues It's now done 104k.
The intervals between topping up are dependent upon how you've been driving your car, the harder you drive the more oil you'll use.

Relax & let the system do its thing

Thanks mate

Yeah I have decided just to let it settle down, drive the car and see how it goes. I went a good run yesterday around 70 miles with no problems. Its still registering full which as I said I'm pretty confident thats correct. Going by previous experience I would expect see that drop 1 bar within the next 300-500 miles, if it doesn't I will then investigate further.

When you say about putting out blue smoke would that be as a result of too much oil or not enough ?

[AWSAWS]

With other tools you can actually see the true oil level.
The car only informs you about the top 1 litre. So full is full and red warning is around 1L down on the 6.5 litres or whatever it takes.

I don't like to rely on this as I don't like letting the car run on anything less than full. The carly app lets you see the info. 255 seems to be full on the raw reading.



It gives me piece of mind. The car itself checks every now and then and if you aren't on a level surface it can give you some odd readings. The sensor sits at the back of the engine towards the firewall so if you are sat on a downhill you can get a low reading.

[Mark e90]

Hmm interesting. What is your car showing on the dash with it at 85%

[AWSAWS]

Originally Posted by Mark e90

Hmm interesting. What is your car showing on the dash with it at 85%

Funny enough the 85% seems completely wrong and it's the same on everyone's car. It's a good job I found out because adding 15% would have overfilled the car.

The car takes 6.5 litres from what I hear. This seems to be divided into 255 on the raw value readout.

So 246/255 = 96.5% full

6.5*0.965 = 6.27 litres

6.5 - 6.27 = 0.23 litres below full.

As expected the Idrive was showing anywhere between full and 3/4 full.

Best thing to do is take a reading after a fresh oil change and record the value. Then you can top it up little by little and take a reading to make sure you don't overfill. The app's readout is very accurate. It continuously updates second by second, unlike the Idrive's once in a while. Be on a level surface when you do it obviously.

[AWSAWS]

As you'll see here:




122%


Rely on the raw oil level sensor number.

[abeardo83]

I have a friend that designs the oil level sensor and it is a clever bit of kit. It will always give a reading saying to top up if it needs it. You'll never have a scenario where your sensor tells you that you're fine, but your engine is starving.

If they do error, they will tell you that they have an error and need to be replaced / inspected.

[Mark e90]

Originally Posted by abeardo83

I have a friend that designs the oil level sensor and it is a clever bit of kit. It will always give a reading saying to top up if it needs it. You'll never have a scenario where your sensor tells you that you're fine, but your engine is starving.

If they do error, they will tell you that they have an error and need to be replaced / inspected.

Thanks mate that gives me some piece of mind that there is not a problem.

I also realised I had not topped up since I changed the oil, I looked back at what the millage was and turns out I have done 1200 miles so it actually makes perfect sense as I said before I find it drops 1 bar per 300 miles so that is spot on, its just caught me by surprise as I don't usually go that long before topping up and usually keep it sitting at full

[AWSAWS]

I basically had a scenario where my idrive was screwed up and I didn't trust it. Was worried it might read full when it wasn't so it was good to see the raw value and compare with other people.
Anyway. Recoded a module on the car and it was all back to normal.
I'd rather the idrive reading was more like the app but it seems to do the job.

[Mark e90]

Just thought I would post a quick update, After around 50 miles the oil level has dropped down to 3/4 full. This makes sense and even though it was reading full it must have only just had enough oil to register full and was right at the bottom end of full and has now dropped down to the top end of 3/4 full if that makes sense.

Looks like my concern was for nothing and I could have just added the full 1L top up at the time

[Mboon]

I thought BMW would have sorted the engines burning oil after the E46 petrol engines

[creepy coupe]

A BMW tech told me this once. Never try and part fill the oil. If the electronic gauge shows half way up the virtual dipstick. leave it until the car asks for oil and then put in 1ltr. this is the amount between low oil and full.