[talisman311]

So I just changed my oil and only filled it up with 6 quarts. I figured that I would let it idle for 5-10 minutes while I clean up and then I'd check the dipstick to see how much more I need to add. So I check...and it's reading max/OK . Not thinking that this was a good idea, I went ahead and added another .5 quarts and it's still reading fine. Is this thing broke or what?

Also for what it's worth, my drain bolt is on the bottom of the oil pan whereas most of the DIYs I see it's on the side.

[chromisdesigns]

It's not continuous reading, or all that exact for that matter. I believe it only reads full, 1/2 quart down, and 1 quart down (or maybe it's liters). You were probably right on the hairy edge between 1/2 down and full.

Just another reason I don't like the concept!

[ENINTY]

The problem is that people don't understand how dipsticks really work, and how engines contain and use oil. The regular old dipstick you are used to only measures the top quart of oil. The hatched marks or lines on a dipstick show the oil level of the engine for the 5th quart (if it holds a total of 5 quarts of oil), or for example the 6th quart of oil (if the engine holds 6 quarts of oil). The dipstick does not show the level of all the quarts of oil in the engine. So, if the dipstick shows the level of the oil between the lower mark on the dipstick and the upper mark of the dipstick, the engine is 1/2 quart of oil low, not 3 quarts low (if it holds a total of 6 quarts).

The e-dipstick in the E90 behaves the same way, except its measurement system evaluates the level of the oil over a long period of time, so running the engine for a few minutes doesn't allow the e-dipstick sensor to collect enough data to make an accurate measurement. If you read the owner's manual, it says only add oil in 1-quart increments when the indicator shows the engine is 1 quart low. The procedure for changing the oil says to drain the oil, change the filter, and then refill with 7 quarts of oil. What you are doing in your case is the old fashion dipstick method which is to add 1 quart less than the max capacity, run the engine then check the level and top it off as necessary. When you change the oil by opening the drain bolt, all of the oil drains from the crankcase. The engine doesn't mysteriously not let the last quart of oil out of the crank and hide it in there somewhere as a joke so you will over fill the engine with oil; so filling it with only 6 quarts and then trying to top it off with a portion of the 7th quart is not necessary. Just pour all 7 quarts in and close it up.

What you need to understand is the engine can take some amount of more oil than the max capacity (but it doesn't need it) without damage, and the engine will run perfectly fine with 1 or 2 quarts low (unless maybe if you are racing the car on a race track). If the N52/N54 engine is 1 quart low, it still has 6 quarts in it, and it will run forever on 6 quarts of oil.

[talisman311]

Thanks for the info, went ahead and put the rest of the 7th quart in today.

[Tom K.]

Originally Posted by chromisdesigns

It's not continuous reading, or all that exact for that matter. I believe it only reads full, 1/2 quart down, and 1 quart down (or maybe it's liters). You were probably right on the hairy edge between 1/2 down and full.

Just another reason I don't like the concept!

The gauge is currently reading 1/4 quart down in both my BMWs - each with about 6~7k miles since the last oil change.

Tom

[poiney]

bump -- can anyone answer the OPs question?

[2kaccordocoupe]

Can you run a test via one of the BT modules?

[ENINTY]

Originally Posted by poiney

bump -- can anyone answer the OPs question?

Okay, I'll try again. Other than trying to explain that you don't use the e-dipstick the same way as a regular dipstick; the only way to "test" the e-dipstick is to wait until it shows the engine is 1 quart low and then drain and measure the quantity of oil that came out of the engine. And don't forget the 10 or so ounces that sit in the oil filter housing.

The e-dipstick is calibrated to tell the driver when the engine is one quart low on oil. The owner's manual says to only add oil in 1 quart increments, so trying to top off the oil level is not the proper way to use the e-dipstick.

[poiney]

Originally Posted by ENINTY

Okay, I'll try again. Other than trying to explain that you don't use the e-dipstick the same way as a regular dipstick; the only way to "test" the e-dipstick is to wait until it shows the engine is 1 quart low and then drain and measure the quantity of oil that came out of the engine. And don't forget the 10 or so ounces that sit in the oil filter housing.

The e-dipstick is calibrated to tell the driver when the engine is one quart low on oil. The owner's manual says to only add oil in 1 quart increments, so trying to top off the oil level is not the proper way to use the e-dipstick.

Sorry, yes I understand this approach and presumably this is the only way. I was hoping there was some way w/o having to dump the oil.

[IllLojik]

Originally Posted by ENINTY

The problem is that people don't understand how dipsticks really work, and how engines contain and use oil. The regular old dipstick you are used to only measures the top quart of oil. The hatched marks or lines on a dipstick show the oil level of the engine for the 5th quart (if it holds a total of 5 quarts of oil), or for example the 6th quart of oil (if the engine holds 6 quarts of oil). The dipstick does not show the level of all the quarts of oil in the engine. So, if the dipstick shows the level of the oil between the lower mark on the dipstick and the upper mark of the dipstick, the engine is 1/2 quart of oil low, not 3 quarts low (if it holds a total of 6 quarts).

The e-dipstick in the E90 behaves the same way, except its measurement system evaluates the level of the oil over a long period of time, so running the engine for a few minutes doesn't allow the e-dipstick sensor to collect enough data to make an accurate measurement. If you read the owner's manual, it says only add oil in 1-quart increments when the indicator shows the engine is 1 quart low. The procedure for changing the oil says to drain the oil, change the filter, and then refill with 7 quarts of oil. What you are doing in your case is the old fashion dipstick method which is to add 1 quart less than the max capacity, run the engine then check the level and top it off as necessary. When you change the oil by opening the drain bolt, all of the oil drains from the crankcase. The engine doesn't mysteriously not let the last quart of oil out of the crank and hide it in there somewhere as a joke so you will over fill the engine with oil; so filling it with only 6 quarts and then trying to top it off with a portion of the 7th quart is not necessary. Just pour all 7 quarts in and close it up.

What you need to understand is the engine can take some amount of more oil than the max capacity (but it doesn't need it) without damage, and the engine will run perfectly fine with 1 or 2 quarts low (unless maybe if you are racing the car on a race track). If the N52/N54 engine is 1 quart low, it still has 6 quarts in it, and it will run forever on 6 quarts of oil.

Thank you. VERY informative.