I go back and forth as is convienient. Have probably run 20% bio tankfuls in last 100k miles.
If filters were an issue would not occur only when burning Bio.
Is a result of bio's lower cetane rating as compared to D2.
85' 300d Turbodiesel 311K
99' E300 Turbodiesel 311.5K and counting NO MORE. (Totaled by Indie's liability Ins after a major oops)
09' E320 Bluetec 66k