I have a BMW X 5 55reg great car. I’ve had it 6 years 100k in clock and runs like a dream but in the last few years every winter on the start up it smokes badly for about 10 secs then clears itself. Just had a hydro clean to clean the carbon but thats not worked. I changed the crank oil filter last year and that’s not cured it. Has anyone cured this? I’m desperate now. Please help.