 My first BMW to be the last, expensive replacement parts, engine head that sits on the engine block is made of an alloy that can't be refurbished, has to be replaced with a new.  When the Head goes oil seeps into the coolant ruining the coolant system.  When the head is replaced the bock is damaged and has to be replaced. The bolts for mounting head onto the block often damage the block, thus making it obsolete.  Read internet response to this particular model overheating.  It's a shame BMW hasn't addressed the issue nor recall the poorly design Head. 