How do you REALLY ever know the oil level?

[TX135i]

So I was playing around today and decided to run a scan with my OBD II device loaded with with BMW specific software. I got a fault that said I was low on engine oil. I check the oil level almost daily using the stalk and display in the speedo, and it has never shown a low oil warning of any sort, ever. So now I'm not sure if it's actually low or not, or how you would ever really know without draining the pan.

[The Wind Breezes]

What fault did you get? Maybe you got momentary low pressure cornering hard and starving your pump or it was low from before.

Anyway I just trust the electronic indicator, it's pretty awesome and very reliable.

[chesticals]

I hate the electronic indicator, i wish it at least had a backup dipstick.

It seems if my oil is anywhere before halfway between min and max, if i park on any unlevel surface it shows low oil light when i turn it off.

Plus i live on a hill with street parking so i can never get an accurate reading at home

[The Wind Breezes]

Originally Posted by chesticals

I hate the electronic indicator, i wish it at least had a backup dipstick.

It seems if my oil is anywhere before halfway between min and max, if i park on any unlevel surface it shows low oil light when i turn it off.

Plus i live on a hill with street parking so i can never get an accurate reading at home

Problem is with you not the dipstick what do you think is gonna happen with a dipstick anyway? The car needs to be level to read right...just fill it all the way. The electronic indicator is awesome and I have NEVER heard a good argument for why it's not (but I have heard plenty of crappy ill thought out arguments)

[Dmak]

Only way to really know how much oil is in the engine is to drain and measure how much came out. Remeber the drain the oil filter too. That's how the dealer do it. No other way around

[Rob_BMW_PNW]

Originally Posted by The Wind Breezes

Problem is with you not the dipstick what do you think is gonna happen with a dipstick anyway? The car needs to be level to read right...just fill it all the way. The electronic indicator is awesome and I have NEVER heard a good argument for why it's not (but I have heard plenty of crappy ill thought out arguments)

NEVER heard a good argument?

I dont live or drive around any 'hill' like areas, and mine will range from 1/2 one week, 3/4 another, back to 1/2, and then full

[The Wind Breezes]

Maybe the areas you're measuring in are not as flat as you thought. You know you can measure that stuff with a smartphone these days. My gage is extremely consistent and only goes down as the car consumes oil over a few thousand miles.

[Rob_BMW_PNW]

Originally Posted by The Wind Breezes

Maybe the areas you're measuring in are not as flat as you thought. You know you can measure that stuff with a smartphone these days. My gage is extremely consistent and only goes down as the car consumes oil over a few thousand miles.

I wasnt born yesterday I am pretty confident that I am on a flat surface, Ive even measured in my garage with the car just sitting there , being the same level day after day cause my garage floor doesnt warp, and the level will change time to time.

The car doesnt 'add' more oil

Being a few degrees on any incline isnt going to sway it half a quart/liter

[kirill1221]

To add to this, the oil level sensors have been known to malfunction so when you see wonky measurements, its best to just replace it.

[bNks334]

It seems to takes a day or two of driving for the oil level sensor to adjust to changes in oil level after I do oil changes. If you lost 2 quarts of oil overnight I doubt the car will tell you you're low the next morning until it's probably already too late. A dipstick would NEVER tell you this anyway unless you check it every morning lol.

I think the sensor works great though. It will definitely accurately warn drives as they lose oil from normal leaks and blow-by over time...

I do my oil changes so it's very easy for me to check the sensors health. If it says I am full, and I do an oil change and get only 5 quarts out, I know there is a problem lol...

I almost always only put 6 quarts back in after an oil change. The car wont tell me "omg you're .7quarts too low." It only warns if you need >1quart. The next day after putting 6 quarts back in, the car always shows the oil at the lower end of the scale. Adding the final 3/4 quart brings the oil level back to full every time (again give time for the sensor to adjust)!

It's a different process than simply pulling a dipstick, but I'd think there would have to be a damn good reason for you too lose oil more rapidly than the sensor can pick up on and warn you about...

TX135i, I don't believe you got a fault code for low oil. You probably had a fault code for low oil pressure. What was the exact code?

Being a quart low on oil (and the car won't be warning you at this point until you need >1qt) could cause oil starvation and therefore low oil pressure, but that would require some steady state heavy g-forces.

[TX135i]

Originally Posted by bNks334

It seems to takes a day or two of driving for the oil level sensor to adjust to changes in oil level after I do oil changes. If you lost 2 quarts of oil overnight I doubt the car will tell you you're low the next morning until it's probably already too late. A dipstick would NEVER tell you this anyway unless you check it every morning lol.

I think the sensor works great though. It will definitely accurately warn drives as they lose oil from normal leaks and blow-by over time...

I do my oil changes so it's very easy for me to check the sensors health. If it says I am full, and I do an oil change and get only 5 quarts out, I know there is a problem lol...

I almost always only put 6 quarts back in after an oil change. The car wont tell me "omg you're .7quarts too low." It only warns if you need >1quart. The next day after putting 6 quarts back in, the car always shows the oil at the lower end of the scale. Adding the final 3/4 quart brings the oil level back to full every time (again give time for the sensor to adjust)!

It's a different process than simply pulling a dipstick, but I'd think there would have to be a damn good reason for you too lose oil more rapidly than the sensor can pick up on and warn you about...

TX135i, I don't believe you got a fault code for low oil. You probably had a fault code for low oil pressure. What was the exact code?

Being a quart low on oil (and the car won't be warning you at this point until you need >1qt) could cause oil starvation and therefore low oil pressure, but that would require some steady state heavy g-forces.

I'll have to go back and see exactly what it said. I'm sure it was low oil, not low oil pressure or I would have been really alarmed. I change my own oil as well and am very meticulous about the exact amount going on. I probably have 2K miles since last change. It had never shown any low oil, ever, so I was very surprised to see this fault on the OBD.

[Rob_BMW_PNW]

The oil sensor is also a oil quality sensor too, which it can read lower levels if it is getting too 'bad' of quality

[The Wind Breezes]

Originally Posted by Rob_BMW_PNW

The oil sensor is also a oil quality sensor too, which it can read lower levels if it is getting too 'bad' of quality

Can anyone back this up because as far as I know the car just estimates when you need to do an oil change and the estimation has nothing to do with actually measuring the quality of the oil.

[iminhell1]

Originally Posted by The Wind Breezes

The electronic indicator is awesome and I have NEVER heard a good argument for why it's not (but I have heard plenty of crappy ill thought out arguments)

A good argument is the simplest one, the car must be running.


from the owners manual:

"Your car is equipped with an electronic oil-level monitor.
For precise measurement and display of the oil level, the engine must be at operating temperature, i.e. following at least 6.2 miles/10 km of uninterrupted driving. You can have the oil level displayed while you are driving, or while the vehicle is at a standstill on a level surface and the engine is running."


With a traditional dipstick you can check oil level prior to engine start and you also don't need to bring it up to operating temp.
IMO, that can potentially save 6.2 miles of bearing damage from low/no oil.

[The Wind Breezes]

Originally Posted by iminhell1

IMO

I think that's extremely dumb because how often do you check your oil before starting the car, ever, and also you're not just gonna go from filled to no oil pressure without some catastrophic event which is about as likely to fuck you dipstick or not (even if you didn't notice all the oil leaving you probably won't check the car randomly before you start it anyway). Also for real damage to occur you'll need no oil pressure which the car will warn you about IMMEDIATELY. If it's a slow loss the car will nag you well before the point it causes damage, which is way BETTER than with a dipstick, because you don't actually need to do anything to become aware of it.

You might THINK it would be handy with an oil change but really if you fuck up putting the right amount in on an oil change you don't need to be doing those.

[titium]

Originally Posted by The Wind Breezes

I think that's extremely dumb because how often do you check your oil before starting the car, ever, and also you're not just gonna go from filled to no oil pressure without some catastrophic event which is about as likely to fuck you dipstick or not (even if you didn't notice all the oil leaving you probably won't check the car randomly before you start it anyway). Also for real damage to occur you'll need no oil pressure which the car will warn you about IMMEDIATELY. If it's a slow loss the car will nag you well before the point it causes damage, which is way BETTER than with a dipstick, because you don't actually need to do anything to become aware of it.

You might THINK it would be handy with an oil change but really if you fuck up putting the right amount in on an oil change you don't need to be doing those.

+1

it's slightly annoying when doing an oil change but all you need to do it put in 6.5L and it's full. this is what i do and usually check the level on the indicator a few days later always reads full.

putting in the correct amount is far easier imo then filling up to almost full checking dipstick topping up some more checking dipstick again, filling more again and so on.

the only senario i can see it being an issue not having a dipstick which the dipstick would pickup on is if you forget to put the sump plug back on and start the car with no oil. I always check under the car after it's filled for any leaks as well as finish cleaning up so for me it's never going to be an issue.

[iminhell1]

More often that you apparently.

[Gizmo135i]

Originally Posted by The Wind Breezes

Can anyone back this up because as far as I know the car just estimates when you need to do an oil change and the estimation has nothing to do with actually measuring the quality of the oil.

It measures the resistance of the oil and predicts how much water/fuel/contaminants are in it, and from that adjusts the oil service interval accordingly.

Also oil level sensors do go bad quite often... usually it will keep coming up to add oil even though it's at the correct level. As a matter of fact I've seen several cars with smoke pouring out of the exhausts because someone over filled the oil when the car kept telling them to add oil every week... one n20 I had worked on had 14 quarts in it! (They only take 5.5).

[Gizmo135i]

Originally Posted by TX135i

I'll have to go back and see exactly what it said. I'm sure it was low oil, not low oil pressure or I would have been really alarmed. I change my own oil as well and am very meticulous about the exact amount going on. I probably have 2K miles since last change. It had never shown any low oil, ever, so I was very surprised to see this fault on the OBD.

It's possible the oil was low at one point and the car stored a code (it will store a code if the oils low) best thing to do would be to drain and measure the oil... if it's got more then 6 quarts in it you should be fine. then put the oil back in or fill with fresh oil and erase the code, if it comes back then change the sensor.

[The Wind Breezes]

Originally Posted by Gizmo135i

It measures the resistance of the oil

I'm sorry, what? First of all, as far as I'm aware oil sensors are typically either capacitative, ultrasonic, or they heat up periodically and check out quick it takes the sensor to cool down to the oil temperature, which is a very accurate way of determining how much of the sensor is covered in oil (specific heat capacity of different oils may differ minutely which would affect the reading).

Anyway, measuring resistance sounds really, really unlikely because oil is by nature a really great dielectric. Can you give me more info on that?

[Rob_BMW_PNW]

An easy argument is that you can check the oil anytime you want the old fashion way. I don't recall having to replace or depend on a sensor to check the oil the old fashion way

[Rob_BMW_PNW]

Originally Posted by The Wind Breezes

Can anyone back this up because as far as I know the car just estimates when you need to do an oil change and the estimation has nothing to do with actually measuring the quality of the oil.

http://www.e90post.com/forums/showpo...79&postcount=5

All I got on it.