Just had the same happen to mine, apparently this is a common fault on the series 1, have just had to scrap it, only had it a year, my guess is it will end up with a replacement engine and be sold on to some other poor unsuspecting soul, worst of it is I still owe money from buying it & now have no car !!! BMW apparently know about this fault but unless you have bought it through them they will not deal with your complaint, don't think they should be sold, so beware when buying a used one.