before i go anywhere near a Bentley i should sort out what's in my garage. 2015 750Li xDrive, F02, the N63TU, 88k miles. bought it last year from a private seller in Littleton for 19 grand, which in hindsight was the first warning.
it's using a quart about every 1,200 miles. nothing on the garage floor. a puff of blue smoke on a cold start after it sits a couple days, then clean. my indie pulled the plugs in June and the passenger bank ones were oily.
he says valve stem seals, 4,800 with the engine in the car using the spring compressor tool. or "top it off and quit worrying." the BMW dealer in Denver says a quart per 750 miles is within spec, so anything they do is on my money. what would you do at 88k?
not my brand, but half our shop came over from the BMW store down the road and the N63 is their favorite campfire story.
blue puff after sitting is textbook stem seals. oil seeps down the guides overnight and burns off at startup. turbo seals smoke under boost, not at startup. on the TU the seals get done with the heads on, the tool holds the valve up with air and compresses the spring. 4,800 is a fair indie number. a dealer will be closer to 7.
bigger question is what else is due at 88k. valve cover gaskets, the coolant lines in the valley, the injectors if they're still the original index. do the seals, then have the turbo oil feed lines start weeping next spring, and you'll be mad you didn't do them together.
had a 2013 750i before the Audi. did the seals at 71k and the smoke stopped, consumption went from a quart per 1k to roughly a quart per 3k. helped, didn't cure it. sold it six months later anyway when the timing chain guides started rattling on cold mornings.
i sell these on the wholesale side. an F01 or F02 with the N63 and 80k plus gets hammered in the lanes like it's contagious, plenty of dealers won't retail one at all. a 750Li like yours is probably a 13 to 15k car at auction today, seals or no seals.
so the math is short. keeping it three more years, do the seals and everything marcus listed while it's apart. selling inside a year, top it off and let the next guy find out.
have them look at the crankcase vent while they're in there. on a buddy's 550i the smoke turned out to be half stem seals and half a torn vent diaphragm in the valve cover.
update. the indie did the stem seals plus both valve cover gaskets, 5,650 all in. 1,900 miles since and i've added maybe half a quart. no puff this morning and it was 28 out.
the VIN lookup on the BMW USA site showed one open campaign too, nothing to do with oil, a seat belt item. dealer did it free in 40 minutes. keeping it for now. the Bentley fund went into a BMW engine, which feels about right for me.
