I have been pouring a litre of oil into my 550i roughly every 1500 km..seems excessive given what im used to. I put in mostly highway miles to and from work daily. Now I noticed grey/bluish smoke coming out of my tailpipe. I recently had work done towards this problem 4 months ago and now this. Car is under extended warrantee but im growing suspicious that the adjuster is only approving bandaid solutions and that when the warrantee expires in 15 months, only then will i be faced with a major repair job. Any comment........i'm seriously thinking of trading it in for a new one but would prefer not to.