DEF is not a fuel additive and never comes into contact with diesel. It is stored in a separate tank, typically with a blue filler cap.
Diesel Exhaust Fluid (DEF) X5 E70 (2007 – 2013). They determined that BMW issued an advisory that the fluid did not have to be changed, .
My 2011 X5 35d does not appear to be using any DEF Fluid. The system has not and is not currently generating any error faults, that can be .
. X5 with BMW Advanced Diesel / Only refill the diesel exhaust fluid yourself in exceptional. Do not allow diesel exhaust fluid to come into contact with you.