While carousing ebay I found this statement:

"I'll provide 2 in line fuel filters and a short
screwdriver to change out the in line filter about every 2 to 3 tanks
of diesel (about twice per oil change). If you don't do this, you'll
find yourself losing power at high speeds."

http://cgi.ebay.com/ebaymotors/Mercedes-300D-biodiesel-vegetable-oil-candidate_W0QQitemZ4625279529QQcategoryZ6330QQrdZ1QQcmdZViewItem

__________________
1984 TDT Blue on Blue "Harriet"
314,143 9/29/05- Our first date
351,000 12/29/08- Oh, the places we have gone!

1991 SDL Black on Palomino "Winchester the III"
188,655 8/11/07
218,700 12/29/08

Work vehicles:
MCI-
D4500 125k
D4505 200k
102A-3 1.8Million! and my fav

He must have an infestation. The primary filter should not need renewal that often.

And if you have a blocked filter, you won't loose power at high speeds!!! You will loose it before that.

Agreed.........some of us run the primary for years without any issues. It's probably turning black with fungus. Tank treatment time. Then you'll really go through some filters...........