The x-drive some models have plastic gear that tends to wear out and then the front axle will stop engaging. The actuator motor is pricy but kits to repair are not. Worst case scenario the TC blows chunks. I found a decent used one for $500 with a year warranty. Install was not difficult at all on the 328xi and I don't think the e83 will be much different.

All the 2007+ gas powered I think used the likely to die electric water pump but I don't know about the diesel. If that fails get a lifetime warranty one and do the thermostat at the same time because only the N62 alternator bracket is worse.

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)