I blanked my EGR valve a couple of years ago. I have a 2007 ST TDCI. It runs much better and smoother. Only downside is engine management light on all of the time. I can live with that. To my mind, if there are cooling, or oil pressure problems or generator problems, these are covered by their own warning lights. , I would If the car seemed to be having another issue elsewhere I would have the codes read.