'06 Dirty Oil

[C. D. Day]

I've got an '06 5.9 with 10,237 miles on it (as of yesterday) When I check the oil it seemed very dirty (black)
A little back round The truck was a factory demo unit placed at the Ohio Dealer, asked dealer to change oil when I pruchased it, but am not sure he did, so I changed oil and filter at 67XX miles the first weekend. I again changed the oil and filter yesterday, (4000 miles on oil and filter) and the oil was black as could be. The old was hot when dropped. I use Delo 400 and standard Fleetguard LF3972 filters. I plan on changing the filter only at 2000 miles to see if it makes a difference, but it doesn't seem the filter has enough filtering capacity although it was heavy when I removed it. There was no oil added or needed between changes. Kinda' like the oil out of an old GM 671 at 20k miles.

Has anybody heard of this being a problem or is it a sign of the common rail system.

Any suggestions or thoughts would be appreciated.

Denny