Most F85/86's are well under 100K miles but I thought I would also post this here for future use and for the few that are or about to have their warranty expire:
The N63, S63, N63TU, and S63TU used in the E70, F15, & F85 are unique in that they all share the same oil pump and drive chain design up to the 2018 model year. Unlike the S63 & S63TU used in the M5, this chain drive does not have a tensioner so it is very likely and almost certain the drive chain will eventually become loose and is something that should be checked every 80-100K miles. I recently checked mine after reading some stories of engine failure and was lucky I did, it was more then 10 times out of spec and about to fall off.
BMW made access to the oil pump and chain adjuster pretty straight forward. It will only add an extra hour or so to your normal oil change time. As a bonus, the lower pan gasket that is notorious for leaking as these engines age is replaced as part of the process. Below are instructions, parts and tools needed plus a short video on the adjustment procedure.
Parts Needed (parts are the same for all engines and all platforms):
(1) Lower Pan Gasket # 11137566808
https://www.fcpeuro.com/products/bmw...x5-11137566808
(25) Oil Pan Bolts # 07129909333 (you can save money and use Loctite 242 or other removable Loctite on old bolts)
https://www.fcpeuro.com/products/bmw...mw-07129909333
(6) Reinforcement plate bolts (Do not reuse, these are one time use only) #33306772888
https://www.fcpeuro.com/products/bmw...er-33306772888
Gasket Tack:
https://www.amazon.com/Permatex-8006.../dp/B000HBNV9E
Tools Needed:
Torque Wrench
Torque Wrench Angle Gauge
Cordless Ratchet (highly recommended, 31 bolts to remove and reinstall)
3/8" extensions
8mm long reach hex socket
T45 Torx socket
E10 External Torx socket
16mm Socket
Instructions (short video below with more details on chain adjustment):
1 - Drive up on 4 ramps or jack up truck as level as possible.
2 - Drain Oil, Reinstall oil drain plug.
3 - Remove the Reinforcment plate.
4 - Remove Oil level sensor connector(Fig.1)
5- Remove the 25 E10 Torx bolts (Fig.2) holding on the lower engine pan (Fig.3).
6 - Remove the oil pump rear T45 torx bolt (Fig.2)
7 - Tighten chain adjuster using 8mm hex socket (see video for more info)
8 - Adjust to 10-12mm total (5-6mm side to side) chain movement.
9 - Reinstall Oil Pump T45 Torx bolt, tighten to 27Nm.
10 - Clean lower oil pan and Install new gasket, (ridged side faces towards engine), use gasket tack to keep in place.
11 - Replace 25 E10 Torx bolts with new or apply removable Loctite 242 to threads if reusing the old bolts and install lower pan. Tighten in standard crisscross pattern all bolts first to 10Nm, then 24Nm.
12 - Replace oil filter & refill oil.
13 - Install reinforcement plate and Tighten new bolts to 56Nm, then use Torque Angle Gauge and further tighten an additional 90 degrees.