What is it? I cut open my old fuel filter and it looked like many of the pics posted. The pleated media was approx 75% blackened. As far as I know, Diesel fuel is somewhat clear. Or at least it looks that way when it gets all over my hands at the filling station! ):h

Thanks.
Rich

That Black Stuff is your filter doing it's job.........

T:cool: NY

The "black stuff" is "asphaltines"
See Diesel Fuel Contamination and Fuel Filter Plugging (http://www.filtercouncil.org/techdata/tsbs/95-1.html)

"Asphaltines -- are components of asphalt that are generally insoluble and are generally present to some extent in all diesel fuel. These black, tarry asphaltines are hard and brittle, and are made up of long molecules. Fuel with a high percentage of asphaltines will drastically shorten the life of a fuel filter"

:)