[arachnyd]

Trust me I searched, and this has been covered like aunt jemima covers my pancakes, but my issue appears to be different.

I don't get the oil level sensor failure warning, I get +1 quart.

I add a quart, and the +1 quart doesn't go away and the oil level doesn't move.

My question is, if you need say, 2 quarts, would the bar be FURTHER to the left than the low mark, or is that the lowest it goes?

If it is, then I'll try adding another quart.

If not, and it doesn't change with an entire quart added, does this sound like a sensor failure which I should replace even though the sensor failure doesn't show? or something else?

Thanks!

[brinkmann]

I REALLY hope 2 quarts low is farther to the left than the low mark, but can't tell you one way or another.

[Efthreeoh]

How many miles are on your car? How long do you wait for the reading after you add the quart? Have you waited after several (10) miles and time (20 minutes) of driving?

[BMWUltimateDriv3r]

You may have a bad oil level sensor, caused by sludge in engine from infrequent oil changes.

[Meeni]

Do not continue filling more oil. The sensor is most probably fried and running overfilled will cause serious damages.

[arachnyd]

I don't know how long its been on. Its my wife's car. Its tricky because the warning light doesnt turn on when your driving, it just turns on when you turn the car off!

It has 105k miles on it. Its a 330i, but an 06 so its an e90.

The guy who owned it before me had full receipts and it looks like he cared for it well. Even replaced all the "going to go" soon items right at 90k (water pump, belts, plugs, et al). We've put about 2000 miles on it. I have not changed the oil yet, but Its getting close. Those 2000 miles have taken 6 months or so to do.

When my wife gets home I'll park it until we get it fixed, and she can drive my truck to work tomorrow. I can replace the fuel sensor, but typically based on my research, if the sensor goes bad it gives you a "Bad sensor" reading.

I am an automotive engineer, but this is our first BMW. Its probably cheaper for me to just swap out the sensor AND do an oil change than to take it in for an oil change and then discover the sensors shot. If that sounds like the appropriate course of action, I'll go ahead and order the sensor!

[David1]

That is how it works. It notifies you of low oil when you turnthe car off. My 09 x5 is the same way.

[ctuna]

You have to take two or three readings to get any kind of idea of
whats going on . They take there time to update after you add oil.
And I am not talking under 10 minutes while running . I have to do
multiple drives and take two or three readings before I get kind of
a fuzzy feeling I am topped off.


I just had and oil change recently and I am pretty obsessive about
checking the oil nearly every time I drive the car. So I start driving accross
town and I wait till the oil is warm and it says it's at the halfway mark.
I stop to get lunch head back and its full again. I have had this happen
on multiple occasions . I really think they should have put a dipstick in
its foolproof.
What is BMW's recommended procedure for checking oil now drain and measure it. Lameo
Again the sensor does not update immediately.
You do no how to monitor the level from the BC stalk or idrive it
has a bar graph to tell you the fill level but only measures the top
quart.

There are many other threads here expressing the frustration we feel
with not having a dipstick.

Also if you wish to DIY or do anything else to the car you may find
these links usefull
http://www.e90post.com/forums/forumdisplay.php?f=16

http://www.e90post.com/forums/forumdisplay.php?f=378

http://www.google.com/url?sa=t&rct=j...,d.cGE&cad=rja

[nate5ks]

Get an oil change and see if it goes away. If not, it's the sensor most likely.

[Three_thirty_I]

I know that it shows an above max level in the case of too much oil being added, but not sure if it shows an under min level. If it was my car I would think about replacing the oil level sensor and change the oil so that it has the correct oil level. And yes, I change oil at 10k km intervals which in my case is once a year - so one oil change done by the dealer, then another roughly a year (10k km).

[Efthreeoh]

Originally Posted by BMWUltimateDriv3r

You may have a bad oil level sensor, caused by sludge in engine from infrequent oil changes.

This isn't true. I changed mine after 225,000 miles. My average OCI is 17,500 miles. The sensor had no sludge in it. I just cleaned it last weekend with electro cleaner and brake clean and shop air, there was no sludge inside the sensor.

[Efthreeoh]

Originally Posted by arachnyd

I don't know how long its been on. Its my wife's car. Its tricky because the warning light doesnt turn on when your driving, it just turns on when you turn the car off!

It has 105k miles on it. Its a 330i, but an 06 so its an e90.

The guy who owned it before me had full receipts and it looks like he cared for it well. Even replaced all the "going to go" soon items right at 90k (water pump, belts, plugs, et al). We've put about 2000 miles on it. I have not changed the oil yet, but Its getting close. Those 2000 miles have taken 6 months or so to do.

When my wife gets home I'll park it until we get it fixed, and she can drive my truck to work tomorrow. I can replace the fuel sensor, but typically based on my research, if the sensor goes bad it gives you a "Bad sensor" reading.

I am an automotive engineer, but this is our first BMW. Its probably cheaper for me to just swap out the sensor AND do an oil change than to take it in for an oil change and then discover the sensors shot. If that sounds like the appropriate course of action, I'll go ahead and order the sensor!

This is a bit more information that is helpful. What I think is the engine has been a quart low for a while and your wife did not understand the notification (it's not intuitive - no offense meant to your wife). The system is designed to add oil in 1 quart increments, meaning it does not tell you when the engine gets lower than one quart low. So you could have added a quart and it may still be a 1/2 quart below having 6 full quarts in the sump. When the low oil notification comes on, per the owner's manual instructions, you are supposed to top off the engine with 1 quart of oil within the next 120 miles. The sensor reports oil level to the ¼ quart increment. If the engine gets lower than 1 quart the system can’t tell you.

I've had my car for 7 years and 227,000 miles so I know the early E90s pretty well and I’ve heavily researched the oil monitor system. I thought I had a bad sensor too just a few weeks ago. I changed the sensor myself and it turned out it was not bad (confirmed by a BMW dealer afterwards). My advice to you is to change the oil now (if you are that close anyway). Follow the correct procedure, which is to open the oil filter housing first, open the oil fill cap (both to allow better draining) and drain the oil. Then pull the few ounces of remaining oil from the oil filter housing, install a new filter, and refill the engine with 7 quarts of oil. Do not fill it with 6 quarts and then try to get a reading and top off with the 7th quart (as some mechanical dipstick car procedures say to do); just add all 7 quarts at one time. Then let the engine run with the oil for a while (several drive cycles) and then take a reading. I do not think the sensor is bad. You are correct when it is bad it does not give a reading and there will be trouble codes in the ECU showing the sensor is bad (my car did not have them, the shop foreman said the sensor is only bad when there are codes indicating so). Change the oil yourself and measure the quantity of the old oil in the sump when you drain it. On several occasions in the past 227,000 miles I measured the drained oil and found the sensor reading to be very accurate.

If you don’t want to change the oil now, then add oil in ¼ quart increments and let the engine cycle for a few drive cycles to take another reading. But if it were me, I’d just change the oil. I recommend using BMW's oil and filter (it’s all I’ve ever used). Several on-line vendors sell an oil change kit for around $75.

This link will provide more info about the sensor. Start with post #26. Ignore the crap from Clifton...

http://www.e90post.com/forums/showth...5#post14551375

PM me if you need more advice.

[F32Fleet]

Excess moisture from short tripping the car could be causing a problem with the sensor reading correctly. IIRC in the past the dealers would vent the excess moisture by idling the car for 10 mins at about 3k rpms with the oil cap off.

Your probably over filled.

[arachnyd]

Originally Posted by Socom

Excess moisture from short tripping the car could be causing a problem with the sensor reading correctly. IIRC in the past the dealers would vent the excess moisture by idling the car for 10 mins at about 3k rpms with the oil cap off.

Your probably over filled.

Unfortunately thats a possibility. The car drives precisely 14 miles a day- 7 miles to work and 7 from work. I need to drive it more often to give it some extended workouts.

I got a LOT of smoke out of the oil cap, and it was white, which is water. Oil would cause the bluish, so that may be the issue.

Originally Posted by Efthreeoh

This is a bit more information that is helpful. What I think is the engine has been a quart low for a while and your wife did not understand the notification (it's not intuitive - no offense meant to your wife). The system is designed to add oil in 1 quart increments, meaning it does not tell you when the engine gets lower than one quart low. So you could have added a quart and it may still be a 1/2 quart below having 6 full quarts in the sump. When the low oil notification comes on, per the owner's manual instructions, you are supposed to top off the engine with 1 quart of oil within the next 120 miles. The sensor reports oil level to the ¼ quart increment. If the engine gets lower than 1 quart the system can’t tell you.

I've had my car for 7 years and 227,000 miles so I know the early E90s pretty well and I’ve heavily researched the oil monitor system. I thought I had a bad sensor too just a few weeks ago. I changed the sensor myself and it turned out it was not bad (confirmed by a BMW dealer afterwards). My advice to you is to change the oil now (if you are that close anyway). Follow the correct procedure, which is to open the oil filter housing first, open the oil fill cap (both to allow better draining) and drain the oil. Then pull the few ounces of remaining oil from the oil filter housing, install a new filter, and refill the engine with 7 quarts of oil. Do not fill it with 6 quarts and then try to get a reading and top off with the 7th quart (as some mechanical dipstick car procedures say to do); just add all 7 quarts at one time. Then let the engine run with the oil for a while (several drive cycles) and then take a reading. I do not think the sensor is bad. You are correct when it is bad it does not give a reading and there will be trouble codes in the ECU showing the sensor is bad (my car did not have them, the shop foreman said the sensor is only bad when there are codes indicating so). Change the oil yourself and measure the quantity of the old oil in the sump when you drain it. On several occasions in the past 227,000 miles I measured the drained oil and found the sensor reading to be very accurate.

If you don’t want to change the oil now, then add oil in ¼ quart increments and let the engine cycle for a few drive cycles to take another reading. But if it were me, I’d just change the oil. I recommend using BMW's oil and filter (it’s all I’ve ever used). Several on-line vendors sell an oil change kit for around $75.

This link will provide more info about the sensor. Start with post #26. Ignore the crap from Clifton...

http://www.e90post.com/forums/showth...5#post14551375

PM me if you need more advice.

Thanks for your pointers. I went ahead and changed the oil with precisely 7 quarts. I'll know later this evening if its reading right now.

Great information about the level/feedback it offers.

These BMWs are certainly not intuitive to me, but we're getting the hang of it... and likely going to get a newer one sooner than later. Owning one is making us believers!

[Three_thirty_I]

Short trips don't do these engines (most engines generally) any good. Moisture from frequent short trips can build up in the oil and usually cause a bit of a scare when a car is driven on the open road for a proper drive, then all of a sudden the oil level appears to have fallen, as in perceived sudden oil consumption. This is the moisture burning off and allowing the oil level to drop, in other words, the oil level has actually been decreasing slowly but moisture adding to the level over time does not make it seem as being the case. It is very possible as said above, the oil level may have been sitting on the min mark for a while and the level dropping more - so adding a quart (1 ltr) may not show as being up to max. Stupidly with this electronic dipstick you can't "top-up" the oil as and when the level drops which is actually pretty important for these 6's, but you can safely add 500ml (half a quart) once the oil level reaches 25%, that way it will always be somewhere between a quarter and three quarter above min - so never min or possibly over max which is also a not good.

[David1]

BS! Moisture does not change oil level. If you had that much moisture to change the level, your motor would be done long ago. The vapor is also combustion gasses.

[Three_thirty_I]

Originally Posted by David1

BS! Moisture does not change oil level. If you had that much moisture to change the level, your motor would be done long ago. The vapor is also combustion gasses.

Fair enough, but no need for the BS comment! We are all trying to help here, and some have different views and experiences. Engine technology also changes and it is a well known fact that moisture CAN build up in an engine. The extent is of course based on that particular engine and the severity of the short trips etc. Yes, I agree, in most cases any moisture from engine warming up temperatures should form part of the combustion process, but this does not mean to say that continuous short trips where an engine possibly does not get up to proper operating temperature can't still cause some degree of moisture in the oil. I was also saying this more in a general sense and not so much in the case of the OP - but rather a case of what people experience in general with engines all of sudden showing a drop in oil level (not necessarily a massive drop) after a long journey when usually the car does mostly down driving. This sudden drop is usually thought to be a sudden indication of the engine using oil, when it is possibly just this moisture that has been allowed to burn off properly - this moisture sits at the bottom of the sump since water is more dense than oil.

[Efthreeoh]

Originally Posted by David1

BS! Moisture does not change oil level. If you had that much moisture to change the level, your motor would be done long ago. The vapor is also combustion gasses.

I agree, the amount of water condensation that would affect an oil level measurement in an engine would long kill the engine before it would be noticeable as a change in level on the dipstick. However, since the N52/N52 doesn't use a mechanical dipstick, water may be affecting how the oil level sensor reads the oil level in the engine. The oil level sensor measures the oil dielectric in a capacitance tube in the oil pan. The tube has two capacitors stacked on top of each other. The bottom reads oil quality and the top of the tube measures the oil level. Water in the oil will affect the dielectric of the oil and possibly give a false reading. Giving that the OP has been experiencing varied readings over short duration, water could be an issue.

[Three_thirty_I]

Originally Posted by Efthreeoh

I agree, the amount of water condensation that would affect an oil level measurement in an engine would long kill the engine before it would be noticeable as a change in level on the dipstick. However, since the N52/N52 doesn't use a mechanical dipstick, water may be affecting how the oil level sensor reads the oil level in the engine. The oil level sensor measures the oil dielectric in a capacitance tube in the oil pan. The tube has two capacitors stacked on top of each other. The bottom reads oil quality and the top of the tube measures the oil level. Water in the oil will affect the dielectric of the oil and possibly give a false reading. Giving that the OP has been experiencing varied readings over short duration, water could be an issue.

That is true, the oil is monitored from how I understand it and as you say, and this is how the condition based oil service interval is determined.

[David1]

Agreed.

[RevALot]

I just had my oil changed about a week ago. It has always read 100% full after an oil change at the BMW dealership. This time however, it only reads around 75% full, which is exactly what it read when I took it in for the oil change. Is there any way I can verify that they actually changed the oil, and just didn't reset the oil 'counter'? I just bought another quart to add to see if it goes to 100%.