So I decided to take my F30 in to a BMW specialist and do a “pre-purchase” inspection... well more like post-purchase by now. And low and behold...
Bent Rim from the inside.
Oil plug and sensor dripping.
Some other stuff showed up too, like the burnt blower fan which I made them replace before I bought it, the warning was still there, and my failed attempt at updating the Bluetooth software, and they said the shitty paint repair job the used car dealer did was... shit.
Lesson learned, insist your mechanic do a more thorough PPI and ACTUALLY PUT IT ON A LIFT to check everything. I guess on the bright side, the specialist mechanic gave a thumbs up to everything else, no structural damage or anything. Now if you excuse me, I’ve got some yelling to do.
UPDATE: Used car lot is taking it up. Got a new gasket for the sensor and a new drain plug. Will monitor it for the next 2 weeks before it goes into storage, but I’m confident that’s the only issue. It was actually seeping around the sensor when they took the shield off.