My husband bought me a 2012 Z4 in Sept 2015. It had had a new wing as a Cat C insurance. I have driven it with no problems for 15 months and it has done 23000 miles. At the weekend I was on the M6 and I lost power, the engine started making a serious rattling noise and as I pulled on to the hard shoulder the engine cut out. It has completely seized. I got it to Rylands in Warwick where they emptied the oil out, very black and tracly apparently. They won't apply to BMW on my behalf because the suspension has had a non BMW replacement part- presumably during the repair and they say the sump looked as if it had been glued on! The last service was done by our local garage NOT BMW and they tried to accuse him of using the wrong oil. He was pretty upset by this and showed us his invoice for the correct oil. They've quoted £11000, for an engine rebuild. I love my car and I'm devastated. Whether the suspension part is wrong has no bearing on the engine and the sump didn't either according to their service manager! 23000 miles and it's died, my husband thinks it was probably the timing chain, do they often have problems with this? :x