Algae or asphaltine?

[Rawze]

(07-25-2017 )Vjex Wrote:  Hi guys, a friend of mine just bought 2011 Volvo with volvo d13 engine, 560k miles.He's got 5000 miles on new oil and fuel filters and that's how his primary davco filter looks now. Is it algae or asphaltine, or just bad biodiesel? He only fuels at Pilot/Flying J. Truck was sitting in a lot for over a year before he bought it.No way to check the tanks, fuel lids are under the cab.Truck runs ok. Fuel filter is 25 micron.

I run a 10 micron filter. after 5,000 miles the bottom half of it is black. After 10,000 miles, most of it is black and the fuel is half way up it. After 20,000 miles the fuel is close to the black line at the top indicating it needs replacement soon and the whole element by now is completely black.

THERE IS ABSOLUTELY NOTHING WRONG WITH MY TRUCK OR ITS FUEL SYSTEM!.

In fact, I have never seen a truck fuel filter that did not turn black by the time is needed replacement. Problem is that most guys don't put fine enough filters on their fuel systems to keep buildup at bay.

Mine has done this since the truck was brand new. It now has over a million miles on it. All that black in my davco filters on my own truck is asphaltene buildup. I had it tested once. A 7 or 10 micron filter will keep it at bay. A 25 or 50 micron filter will only catch about 15% of it and the rest keeps circulating around and building up until is takes over the fuel system.

Start running 10 micron filters and dump some bio-cide in the tanks to kill any algae in the mean time. -- keep spare filters and a wrench to replace them in the truck just in case it is algae.