An '07 328 engine holds 6.9L of oil. At what level BELOW that 6.9L "full" level should the electronic oil level gauge read anything less than max full? What are BMW's factory specifications/tolerances for this critical gauge? I have asked this on a couple of forums but have not received a knowledgeable response. The reason I ask is I changed the oil and filter in my wife's '07 328 Conv. at 1,500 mi. and initially refilled it with 6 qts. I then ran the car for about 5 min. and checked the oil level with the electronic gauge, which read 100% full (??). I did NOT add any more oil to the system at this time. The next time the car was driven was a 45 mile drive and at the end of the drive I checked the oil level again but it still read full. It wasn't until I had put almost 300 mi. before the level finally dropped to 3/4 full, at which time I added .25 qt. of oil and again it now reads full and has for the last 2,000 mi. A few additional items: 1) Oil was drained while the car was on my lift, all oil was drained, plug was out for 5+ min. after filter was changed. 2) New BMW oil, filter and crush washers were used 3) Other than the first oil level check after the oil change I only check the oil after a 30 min. drive at least and let the car idle for a min. or so, usually at a gas stop before actually checking the oil level. 4) I've worked on all my cars for the last 30 yrs., including 4 Porsche's, 5 BMW's and many others. 5) Give me back the damn dipstick, they can't be that expensive on a $50K vehicle! In my opinion there are 3 things BMW needs to do to get this enthusiast interested in it's new cars, return the dipstick, include a spare tire and make a speedometer that reads a LOT closer than the 7% high that my wife's car reads! Our '06 Porsche Cayenne S's speedo is dead on accurate and they abide by the same Euro regs. BMW is claiming to suffer from.
Why didn't u just fill it to 6.9l. Are you doing a test to see if u can break the engine without any warning lights coming on? Be smart, don't reply in these gauges when u know better. I'd assume that a good .25 or so qts can be accounted for in the filter and all the wet surfaces combined. Maybe this 6.9 is just a total, for oil filter and what's left in the pump and all that. So maybe the actual sump amount needed is say 6.6 or so. Factor in the margin for the warning light, to about .5 qt or so, and that's probably why. Depending on where the sensor is, (I don't know if they moved it in the E90s) and how smart it has become, maybe it reads over as wide a range as 1qt, that gives enough room for g force loads, what's in the filter, the pump, the lines etc. I'd imagine very few people would have access to this information though. Good luck finding it, but stop chancing it man
What an a-inine response! Why would running the car .9 qt low be a risk of braking the engine when the actual ADD mark isn't until the 1 qt. low? Even the older cars with the dipstick didn't have the add mark until the 1 qt. low level. I'm actually glad I did it this way because I now know the electronic system can't be trusted and I am investigating what the problem may be, how it can be diagnosed and how I can prove it to BMW to get it resolved. But, as the old saying goes, ignorance is bliss.
Well, that's all good and merry, but my thing is, if it asks for 6.9l or qts whatever, why did u stop at 6? Engines can be very weird man, sometimes that little bit that your off is enough to make another component operate with low pressure and then that throws off another thing and before u know it, the engine fails 20k later and u don't have a clue why. That's all I'm getting at. Its all good tho. I'm glad u have solid proof that those sensors are shady.
Don't know if this helps, but I found it interesting. Attached is a document I found describing the oil sensor used in the N52 (and I presume N54) engine. I can understand how it could give inaccurate readings. I really would like a dipstick, as I like to keep my engine full at all times. I hate the thought of running .9 Qt low and not knowing it.
Very interesting, thanks for posting it. I can see where this sensor would have to be replaced when the oil was drained. Since the dealer will be performing a oil and filter replacement (free) at the 1 year mark I'll get them to do a oil level check (thru the system) then measure the oil they drain out to see what the discrepancy is, if they don't choose to replace the sensor after that I'll revisit the issue. I REALLY hate the idea of overfilling the oil just to avoid problems with faulty sensors.
