The N62 has a horrible quirk that may also exist on M62: the alternator bracket has a $3 "o-ring" (shaped like Micky mouse) that takes about 4 hours to replace and is no fun. When it blows it will squirt oil as fast as you can pour out of a bottle (literally not an exaggeration). It can be DIY and you should be prepared for that to happen on >150k miles. If I bought one older than 150 I would change preemptively. The one I helped replace was hard as clay.

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