Don't bother, I have only done it twice on my car in 54k and 4 years of driving it, most of the time it made little to no difference. Drive it hard and it will run fine forever without diesel purge. I usually purge and replace the filters every 1.5-2 years. Usually around 2 years.

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-diesel is not just a fuel, its a way of life-
'82 300SD 320k -mine Parting out this summer. (OC-323,450)
'89 420SEL 146k - mine (OC-147,500)
'93 190D 2.2 - 208k - mine (OC-210,100)
'13 VW GolfWagon TDI 6Speed - 0k - wifes
'82 300SD 340k -dad's (OC-341,200)
'87 420SEL - 305k - dad's - (OC-309,400)
'83 300D 258k - brother's (OC-261,150)
'12 VW Jetta - 7k - Sisters