When i saw this thread highlighted in my mailbox under trending m5board posts, I immediately jumped to it. I have much to say about this.Just my 2 cents here..
I've done a bunch of reading on the twin turbo V8's in modern 550i's and 650i's being horrendous with oil consumption straight from the factory. When I went to the free BMWCCA undercarriage event this past winter, I was talking to the master tech and he said their biggest pain in the A right now was FULL engine replacements and many many many of them due to excessive oil consumption - even engine seizure.
Might be a class action lawsuit, but appears to be a link here already for that. Just saying, IDGAF what BMW thinks is "normal oil consumption" one quart every 350 miles is straight bullshit. My E46 330i had constant issues with oil consumption, seemed like I was always adding it, keeping the oil companies in business even after I buttoned up every single seal on that engine. Contrary to that, my E39 M5 barely consumes any between oil changes, has a small very very slow weeping valve cover gasket leak,. but otherwise is incredibly solid as far as oil goes even with almost 100K miles. The M52 engines were incredibly stout and had zero issues with piston rings, the M54 was plagued with this, and now it seems that the new twin turbo V8's are too.
It's a design flaw, no engine should consume that much oil other than a top fuel dragster pushing the metal to it's physical limits. AND IF IT DOES FOR SOME REASON, IT SHOULD BE CLEARLY STATED ON BILL OF SALE RIGHT IN THE PURCHASER's FACE: "****NOTE: THIS ENGINE WILL CONSUME OIL AT A RATE OF 1 QUART EVERY 350 MILES, AND IT IS UP TO THE OWNER TO REPLACE THE OIL.*****"
Hiding this fact, while being aware of it is shady tactics, and most certainly telling your customers that it's "within acceptable limits" is utterly bullshit.
Trizzuth you are right, everything, every word.
I bought a factory delivery bmw E92 M3 in 2013 (4.0 liter S65 engine V8, no turbo, which is the same engine as the E60 M5 s85 V10 minus two less cylinders).
I flew to Munich, germany to take european delivery of the new car in 2013. After only 380 miles on the odometer, having crossed the border to Italy, i first discovered the Idrive message : "Engine oil low ! please add one quart !" I thought it was some kind of fluke but called BMW germany, after being transfered a few times, a german master mechanic told me in broken english to add 1 quart of 10W60 oil which i did after i found a center to get it (with difficulty on a holliday). He said nothing else. This was to become a continuous issue with the car. Back in the states the dealer bullshited as they do, trying to reassure me improvising various random reasons : "oil consumption will stabilise after break in". They started an oil consumption log but soon forgot about it, within months they gave me a blank stare when i would bring the oil consumption issue to them, they gave me free fill ups whenever the car requested oil but they stopped that immediately the day the car went out of warranty. I kept my own log of having to add oil between oil changes over the years.
I have had to add 1 qt oil every 800 - 1500 miles but that is because i mostly drive it on the local freeway. If i take it on the highway on long distances, the oil sensor level will drop from max level to min level in just 4 hours of highway drive and give me the warning. I know from experence now that if i only drove this car on the highway, it would require 1 quart of oil every 350-400 miles, possibly less, just like during my trip in germany.
The oil sensor was a panacea for the dealer to dodge and confuse the engine's oil consumption, they started blaming it. Obviously they know the engine consumes oil since they've drained the oil to measure it when the warning came on (and they put the oil right back into the car, i emailed bmwna if this is normal practice, i was told it is.) After a long highway drive when driving locally the next few days the oil sensor level ifrom the idrive would pop back up to mid level. I seriously suspect that the lack of dipstick design was purposedly done to hide and confuse the true engine oil consumption.
Here i should mention that i've had so many other issues with the car that the oil consumption was forgotten while i had to battle the dealer to do other needed repairs. I eventually gave up having to fight the dealer under warranty for the oil. Eventually in 2017 they gave me a printed document " SI B11 03 13 August 2016 Updated Technical service bulletin" which is an update on oil consumption from BMW that claims that 378 miles per quart (2.5 liters / 1000 miles) is normal for M cars with "S" engines. I believe your M6 has the S63B44T0 twin-turbo 4.4 liter engine.
Here it is important to mention that I know many other M3 owners's through car forums like this one whose car consumes not a drop of oil, neither during breakup or ever. So this is not just a model specific design issue from BMW but also extremely poor Quality Control. I know other companies have been sued and convicted for excessive oil consumption (with much much lower consumption numbers). I am not aware of any lawsuit against BMW but if there is, I am in.