Without being too model specific, but i'll try.....
1 series (including 2013, 2014 models) and others, timing chains, differential that make horrible noises, ABS reluctor/toothed wheels that corrode and expand and rub the end off the abs sensors (including Z4), any model BMW with valvetronic motors (now down to < £285 at the dealers), vanos seals, window motor regulators, usual Z4 sticky steering, ABS/DSC modules on a lot of models, usual DISA, Many, many vacuum leaks (usually from PCV system hose deterioration), lollipop bushes. Having a run on E85/86 z4 starter motors at the moment, but the cars are getting old now!!
I went over to Warrington recently, over pennines from me, to see a 2012 1 series 116i. Not a short journey, and it was horrible (the journey and the car). Written off twice in first year and a half of its life, 4 different tyres, all 4 alloys kerbed, drivetrain fault and in limited power mode (didn't find out why), interior worn to hell, seats faded, rear discs well worn (but seller said "it passed an MOT with them"). Even the key fob was worn and tatty. And only done 49000 miles apparently.
There are undoubtedly really good ones out there, but I only see the poorly ones. Gives a very biased impression in my head, which is sometimes hard to get rid of.
I can understand why people buy them though. Quite attractive and generate loyal followers.
Shall I buy another BMW? Never say never, but probably not.
i get asked many, many times what reliable car I would recommend buying since I am in the trade. My answer?...... None. Get a pushbike instead. :wink:
Andy.