Oil level?

[CrazyOneToo]

I just had my oil and filter changed a week ago and last night I hit the oil level button on my 2007 Z4
roadster with an N52 engine and this shows up. I drove it around this morning and got it good and warmed
up and the same reading. I asked my mechanic about it and he said it seems it's a half a quart low. I added
a half quart and it still reads the same. Before I got my oil changed it read up to the full line. Thoughts?

[pungo]

That's why I change my own oil, oh wait my Z4 3.2 has a dipstick though my X3 N55 does not. Either your shop did not fill it all the way or your sensor is a little off. I would be careful adding too much more since overfilling is bad too.

[Hatesns]

I also have a 2007 z4 and I change my own oil. Your machanic probably own put in 5 quarts of oil. It needs 7qts. I would add one half gt at a time and recheck you level. Do not overfill.

[CrazyOneToo]

Originally Posted by Hatesns

I also have a 2007 z4 and I change my own oil. Your machanic probably own put in 5 quarts of oil. It needs 7qts. I would add one half gt at a time and recheck you level. Do not overfill.

I have already put half a quart more in it at two different times but it still reads the same. I'm more afraid of over filling it than it being low. If they did put 7 qts and the sensor stopped working that would be bad. It reads OK and does not make noise that would make it seem low. I have read that if overfilled it can destroy the cats. Ugh! This is my first oil change on this car and with no dipstick. I'm paranoid about the oil level. The oil filler cap says Castrol on it but I use Mobil 1 (0W-40) in all my cars. Could that be an issue? Who knows what oil brand or viscosity the previous owner had in it.

[KevinC]

Sounds like oil level sensor is probably bad. Shame on BMW for taking the dipstick from some motors (I assume they're all gone nowadays?).

[XMetal]

Originally Posted by CrazyOneToo

I have already put half a quart more in it at two different times but it still reads the same. I'm more afraid of over filling it than it being low. If they did put 7 qts and the sensor stopped working that would be bad. It reads OK and does not make noise that would make it seem low. I have read that if overfilled it can destroy the cats. Ugh! The oil filler cap says Castrol on it but I use Mobil 1 (0W-40) in all my cars. Could that be an issue? This is my first oil change on this car and with no dipstick I'm paranoid about the oil level. Who knows what the previous owner had in it.

The type of motor oil won't make a difference in oil level readings. If you have access to a scanner, then see if the sensor is bad. Otherwise, I would just drain it and refill so you know exactly how much oil is in there. You can always reuse the oil if it was just recently changed.

This is the main reason why I don't like cars without a dipstick and the main reason why I went away from BMW when we were searching for my wife's DD. Well...that and a spare tire were the main reasons.

[CrazyOneToo]

Originally Posted by KevinC

Sounds like oil level sensor is probably bad. Shame on BMW for taking the dipstick from some motors (I assume they're all gone nowadays?).

I'm guessing they all have a missing dipstick now. That would make a stealership visit more likely.

[CrazyOneToo]

Originally Posted by XMetal

The type of motor oil won't make a difference in oil level readings. If you have access to a scanner, then see if the sensor is bad. Otherwise, I would just drain it and refill so you know exactly how much oil is in there. You can always reuse the oil if it was just recently changed.

This is the main reason why I don't like cars without a dipstick and the main reason why I went away from BMW when we were searching for my wife's DD. Well...that and a spare tire were the main reasons.

Yes I have an Actron CP9185, Foxwell/Schwaben 14020SCG and a Creator C310 but not sure how to check where they would show if the sensor was bad without the car having a code. There are no codes thrown....yet. I think the engine holds 7 qts of oil. I wont be changing the oil filter this time tho. I bought some more oil to switch it out and measure the amount that is installed now. Yes I'll be keeping the 2 week old oil for later. Its getting to be like buying gold. I have an owners manual but it didn't come with the car when I purchased it. I bought it from a BMW dealer, but it was the 3rd one they sent before they claimed it was the correct one. I don't know really. Every page on the net has different info. From what I am finding, apparently the 2007 year was a cutoff and switchover year. Some cars had this and some had that.

[CrazyOneToo]

Originally Posted by XMetal

The type of motor oil won't make a difference in oil level readings. If you have access to a scanner, then see if the sensor is bad. Otherwise, I would just drain it and refill so you know exactly how much oil is in there. You can always reuse the oil if it was just recently changed.

This is the main reason why I don't like cars without a dipstick and the main reason why I went away from BMW when we were searching for my wife's DD. Well...that and a spare tire were the main reasons.

Wow just hooked my Foxwell to the car and checked for codes but none were present. Checked the oil level through the scanner and it showed to be reading full. Then checked the ECU info so I could take pics of all that info and then unplugged the scanner and unexpectedly now the level shows full and OK! .....WTH?!?!?!? I did NOT erase codes or knowingly change anything.

[KevinC]

^^ Sounds like the sensor is failing for sure based on it suddenly deciding that the oil level is fine. I'd get that rascal replaced.

[CrazyOneToo]

Originally Posted by KevinC

^^ Sounds like the sensor is failing for sure based on it suddenly deciding that the oil level is fine. I'd get that rascal replaced.

Yeah but not now since I just changed the oil.

[David70]

I think if it was reading partially full and then suddenly goes back to completely full with no other change that is most likely to be the sensor. I have no idea why this would happen right at an oil change. I would wait a week or two and see if anything changes or if relatively simple just replace the sensor.

As for BMW removing the dipstick because it isn't needed I see zero chance the dipstick doesn't read correctly but this system is far less reliable.

[3798j]

Sure would be nice to know exactly how many quarts the shop put in...6.5 plus your .5, you're right where you want to be. Unfortunately the sensor doesn't show overfills.

[CrazyOneToo]

Originally Posted by David70

I think if it was reading partially full and then suddenly goes back to completely full with no other change that is most likely to be the sensor. I have no idea why this would happen right at an oil change. I would wait a week or two and see if anything changes or if relatively simple just replace the sensor.

As for BMW removing the dipstick because it isn't needed I see zero chance the dipstick doesn't read correctly but this system is far less reliable.

Yes I'm going to wait a while and see how it goes. I changed one out on my X5 and it wasnt hard. But had to remove the reinforcement plate I think. It was not that expensive but it will be more on this car.

[CrazyOneToo]

Originally Posted by 3798j

Sure would be nice to know exactly how many quarts the shop put in...6.5 plus your .5, you're right where you want to be. Unfortunately the sensor doesn't show overfills.

Actually if they put the correct amount in it I am 1 qt over now.
I will have to look in the manual again but I think mine does show if its overfilled.

[Efthreeoh]

I wish I had seen this post at the end of March. I could have helped out. I posted in the E90 Forum in detail how the oil level sensor and oil monitor system work.

https://www.e90post.com/forums/showthread.php?t=1533444

But in short, you are using the oil level indicator incorrectly. It's not your fault. It is BMW's because they've never sufficiently explained how the system works, they expect an owner to take his car into the dealership.

The oil level sensor does two things, it measures the oil quality and the oil level. It measures the oil quality to help determine when to change the oil. It measures the oil level to have a data point for the ECU to protect the engine and operate the VANOS system. The VANOS system adjusts the intake and exhaust timing to maximize horsepower dependent upon engine load. The adjustments are made using oil pressure and flow rate. If the engine is low on oil, the ECU needs to know to control the VANOS system. That is the main purpose of the oil level sensor system. The secondary use is to allow the vehicle operator to check the oil level under dynamic operating conditions (i.e. while the engine is running) using the e-dipstick.

What most likely happened is the tech who performed the oil change did not refill the engine block correctly with oil. He probably used the technique he was taught for an engine with a mechanical dipstick, which is to add a quart less than capacity, then top off after the engine is warmed up (to get oil into the oil filter). This works fine for a direct reading mechanical dipstick engine, but does not work for the N52 with an electronic dipstick (e-dipstick). The e-dipstick requires time, temperature, and operating conditions to get a correct reading of the oil level. The correct procedure for changing oil in the N52 is (1) drain the oil) and remove the residual oil in the oil filter housing, (2) replace the filter, (3) refill the engine with 6.9 quarts of oil. No guess work. This presumes the oil change is being performed on a level car (i.e. not on ramps).

Not repeat the entirety of my linked-to post, but the N52 engine needs at a minimum of 20 minutes of continuous driving to determine a new oil level. Worse, if oil is added and the car is then immediately driven, the e-dipstick will report the incorrect "old" oil level (i.e. before oil was added) once the engine gets warm enough to allow the system to report an oil level. So what happened with you is the e-dipstick was reporting a half-quart low (because the tech probably added on 6.5 quarts to the 7 quart engine oil sump), so you added an additional 1/2 quart to top off the engine but did not allow enough time to get a new oil level reading (i.e. 20 minutes of continuous driving). So you then added the 2nd 1/2-quart and again didn't wait the 20 minutes.

Hope this explains what happened so you'll not repeat the event again. I also suggest you take your car to a BMW shop that is familiar with the N52. And finally, you need to change your way of thinking to understand all automotive engines are perfectly safe to operate with less than a full load of engine oil. Read any owners manual of any street car (i.e. not a race car) on the subject of engine oil level and it will tell you that to keep the engine oil level between the low and high marks on the dipstick. This means to only add oil when the level is at the low mark, which on most engines means the oil level is a quart low; this is no different for the N52 and its e-dipstick system. The reading you got ("OK") meant the engine had enough oil to operate safely and it was not necessary to add the additional 1/2-quart. The N52 should be topped off at 1-quart intervals once the system notifies the operator that the engine is 1-quart low on oil.

[CrazyOneToo]

Originally Posted by Efthreeoh

I wish I had seen this post at the end of March. I could have helped out. I posted in the E90 Forum in detail how the oil level sensor and oil monitor system work.

https://www.e90post.com/forums/showthread.php?t=1533444

But in short, you are using the oil level indicator incorrectly. It's not your fault. It is BMW's because they've never sufficiently explained how the system works, they expect an owner to take his car into the dealership.

The oil level sensor does two things, it measures the oil quality and the oil level. It measures the oil quality to help determine when to change the oil. It measures the oil level to have a data point for the ECU to protect the engine and operate the VANOS system. The VANOS system adjusts the intake and exhaust timing to maximize horsepower dependent upon engine load. The adjustments are made using oil pressure and flow rate. If the engine is low on oil, the ECU needs to know to control the VANOS system. That is the main purpose of the oil level sensor system. The secondary use is to allow the vehicle operator to check the oil level under dynamic operating conditions (i.e. while the engine is running) using the e-dipstick.

What most likely happened is the tech who performed the oil change did not refill the engine block correctly with oil. He probably used the technique he was taught for an engine with a mechanical dipstick, which is to add a quart less than capacity, then top off after the engine is warmed up (to get oil into the oil filter). This works fine for a direct reading mechanical dipstick engine, but does not work for the N52 with an electronic dipstick (e-dipstick). The e-dipstick requires time, temperature, and operating conditions to get a correct reading of the oil level. The correct procedure for changing oil in the N52 is (1) drain the oil) and remove the residual oil in the oil filter housing, (2) replace the filter, (3) refill the engine with 6.9 quarts of oil. No guess work. This presumes the oil change is being performed on a level car (i.e. not on ramps).

Not repeat the entirety of my linked-to post, but the N52 engine needs at a minimum of 20 minutes of continuous driving to determine a new oil level. Worse, if oil is added and the car is then immediately driven, the e-dipstick will report the incorrect "old" oil level (i.e. before oil was added) once the engine gets warm enough to allow the system to report an oil level. So what happened with you is the e-dipstick was reporting a half-quart low (because the tech probably added on 6.5 quarts to the 7 quart engine oil sump), so you added an additional 1/2 quart to top off the engine but did not allow enough time to get a new oil level reading (i.e. 20 minutes of continuous driving). So you then added the 2nd 1/2-quart and again didn't wait the 20 minutes.

Hope this explains what happened so you'll not repeat the event again. I also suggest you take your car to a BMW shop that is familiar with the N52. And finally, you need to change your way of thinking to understand all automotive engines are perfectly safe to operate with less than a full load of engine oil. Read any owners manual of any street car (i.e. not a race car) on the subject of engine oil level and it will tell you that to keep the engine oil level between the low and high marks on the dipstick. This means to only add oil when the level is at the low mark, which on most engines means the oil level is a quart low; this is no different for the N52 and its e-dipstick system. The reading you got ("OK") meant the engine had enough oil to operate safely and it was not necessary to add the additional 1/2-quart. The N52 should be topped off at 1-quart intervals once the system notifies the operator that the engine is 1-quart low on oil.

Thanks for all the info!!! I was just thinking running it low would be better than over filling it.
So if they put the correct amount in and I added 1 extra quart total is it safe to drive my car like that? It is reading full and OK now.

[Efthreeoh]

Originally Posted by CrazyOneToo

Thanks for all the info!!! I was just thinking running it low would be better than over filling it.
So if they put the correct amount in and I added 1 extra quart total is it safe to drive my car like that? It is reading full and OK now.

But that is the point. The level reported was in the middle of the bar graph, which means it wasn't low; it just meant it wasn't 6.9 quarts "full". One of the reasons I wrote the Thread on the oil level sensor was to help people break the habit of topping off their N52/N54/N55 engines to keep the oil level at max. If you own an N52 you have to break yourself of the idea the engine needs to always be at max full level. You can't achieve keeping the engine topped off at full because the oil level system is not designed with that level of precision of measurement that a mechanical dipstick provides. You'll go insane trying to keep an N52 topped at max level. Again, the operators manual for EVERY automotive engine with a mechanical dipstick says that an oil level between the marks on the dipstick means there is a safe level of oil in the engine. Almost every owners manual for a car with a mechanical dipstick engine tells you to only add oil when the level is at the low mark on the dipstick. It is no different for the N52, which is why you add oil at ONLY 1-quart intervals.

I have a Z4 Coupe with the N52, per page 93 of the owners manual, the instrument cluster reports an over-filled condition by showing a block to the right of the e-dipstick graph in the gauge cluster. If the system is reporting ok, then I think it is safe to drive the vehicle. What I would do it take the car out on the highway for 30 minutes and take a reading while at speed and see what is reported.

[CrazyOneToo]

Originally Posted by Efthreeoh

But that is the point. The level reported was in the middle of the bar graph, which means it wasn't low; it just meant it wasn't 6.9 quarts "full". One of the reasons I wrote the Thread on the oil level sensor was to help people break the habit of topping off their N52/N54/N55 engines to keep the oil level at max. If you own an N52 you have to break yourself of the idea the engine needs to always be at max full level. You can't achieve keeping the engine topped off at full because the oil level system is not designed with that level of precision of measurement that a mechanical dipstick provides. You'll go insane trying to keep an N52 topped at max level. Again, the operators manual for EVERY automotive engine with a mechanical dipstick says that an oil level between the marks on the dipstick means there is a safe level of oil in the engine. Almost every owners manual for a car with a mechanical dipstick engine tells you to only add oil when the level is at the low mark on the dipstick. It is no different for the N52, which is why you add oil at ONLY 1-quart intervals.

I have a Z4 Coupe with the N52, per page 93 of the owners manual, the instrument cluster reports an over-filled condition by showing a block to the right of the e-dipstick graph in the gauge cluster. If the system is reporting ok, then I think it is safe to drive the vehicle. What I would do it take the car out on the highway for 30 minutes and take a reading while at speed and see what is reported.

Ok thanks I'll try to relax but that hasn't worked out much in the past. LoL
I will take it out ASAP, maybe this weekend. What year is your car?
When I bought the car used it didn't come with an owners manual.
It took me 3 tries (from BMW) to get what I am told is NOW the correct one.
In the one I have now it shows the overfull message also.
From what I understand the 2007 is a changeover year model. That's always great.

[Efthreeoh]

Originally Posted by CrazyOneToo

Ok thanks I'll try to relax but that hasn't worked out much in the past. LoL
I will take it out ASAP, maybe this weekend. What year is your car?
When I bought the car used it didn't come with an owners manual.
It took me 3 tries (from BMW) to get what I am told is NOW the correct one.
In the one I have now it shows the overfull message also.
From what I understand the 2007 is a changeover year model. That's always great.

Mine is an 2008 Coupe 3.0si. In 2006 BMW swapped to the N52 from the M54 in-line-6 for both the Roadster and Coupe (non-M models). The E85/E86 Z4 is based off the E46 chassis. The E46 used the M52 then the M54 engine and never changed over to the N52.

[CrazyOneToo]

Originally Posted by Efthreeoh

Mine is an 2008 Coupe 3.0si. In 2006 BMW swapped to the N52 from the M54 in-line-6 for both the Roadster and Coupe (non-M models). The E85/E86 Z4 is based off the E46 chassis. The E46 used the M52 then the M54 engine and never changed over to the N52.

Yeah my 1999 E46 has a M52TU. My 2002 E53 X5 has the M54 Engine.
So the engines are mechanically basically the same in each car that has the N52 engine?
I had assumed the Si version had a different engine since the horsepower is higher.

Thanks for all your incredible info!!!

[Efthreeoh]

Originally Posted by CrazyOneToo

Yeah my 1999 E46 has a M52TU. My 2002 E53 X5 has the M54 Engine.
So the engines are mechanically basically the same in each car that has the N52 engine?
I had assumed the Si version had a different engine since the horsepower is higher.

Thanks for all your incredible info!!!

The si has a 3-stage intake manifold and 261HP. But it's the same engine other than that.