Volvo d13 2012 water separator is black after 3000 miles driving wath can be the problem

If the truck sat unused for a period of time that would explain the algae in the tank... Once you have gotten the issue taken care of don't park it for an extended period of time with out first filling the fuel as full as you can get it. this will help to prevent future algae growth.

 

I have same problem, just replaced this filter , looks dirty after 9000 miles, was not full but looks contaminated .This are not algaes , i drive in cold Canada mostly bellow freezing, algaes sgould be dead, looks blueish ,most likely combustion soot. I feel it low on power , i dont remember this problem with my last truck , 2008/ 1.8 mil miles, or i didnt pay attention this one is 2010, 1.1 mil miles.

 

Mine was/is like that as well although it seems to be getting better. When I took mine apart it wasn't slimy like algae would be , it was hard little chunks in the bottom of the bowl, like asphaltine, but I remember that being more of a Cummins problem. I cut open the fuel filter and it hadn't made it that far, the Davco seems to be doing it's job. I still have some black residue in the tanks, more on the passenger side but seems to have stabilized, so I'm not sure if Biocide would do anything.

 

You may need new Injector cups.

 

Yeah it's funny cuz my oil sample came back with a bit of fuel dilution, took some to another independent place and it had a bit as well. Done my oil change and asked Volvo about it and of course they came back with, it's within our tolerances so run it another service interval. So another 12000 miles I get 2 samples again and both came back clean. Go figure.

 

Leaking copper seals

 

Hey gents a question;
I've just replaced injectors today because of the problems described above, been running like this 3 + months/50k miles, but last week was getting lower on power on hills, more and more black shoot in water separator filter, no long cranking at start. They did an injector test , the graph came out bad.
I took the truck from shop and road test it bob, and doesn't seem to pull exceptionally better than before.
My question; does it take some time , burn few hundreds gallons for new injectors to work at full capacity ?! no codes.
I did this job 4 times on my last truck, and i remember a technician told me this, is it true?!

 

I still have the problem with black water separator probably is soot, i have pitting on the head of engine , buth if the washers are instaled good soot should not goo to fuel return line, on my truck yesterday vibration come beck again on diagnostics shows injectors and cylinder pressure is ok but it have some knocking sound, truck runs and have god mpg 6.2 no problem with starting just when turn the key it have sound like engine is working with low power, the truck is on mechanic tomorrow they will open the cover to see wath is the problem.

 

I have a volvo d13 as well and last January I replaced the dayco fuel filter and noticed that it was blackish, not completely just around the edges. Cleaned the filter area, just a little sludge and grit, nothing unusual. I changed it again in early April, a little worse. Had the PM at the end of April done and had an oil test, nothing unusual they said. I changed the Dayco filter again in early June it was black. Took photos to the volvo dealership and the service manager said it was the filter doing its job. I thought differently but you go with what a master mechanic says who has 30 plus years experience. The stacks show no residue, the fuel mileage is at around 6.8 to 6.9 miles per gallon. Power seems normal, engine runs fine, no knocking or odd noises. The only change I have made to my routine is I started adding once a month fuel injector cleaner to both tanks. I have not deleted the ATS. I checked the fuel tanks, the passenger side does have some grit and residue in it but hard to say what it is.

Then 2 weeks ago the truck started sluggishly and has done it intermittently since. Not all the time, it will start on the first crank or two for a few or more times and then it will hard start(crank for 5 to 15 seconds) then start for a few times. It hasn't reached the where I would need to prime it yet. It seems to happen more when the engine is hot rather than cold. I had the injectors and cups replaced November 2015.
Could it be the injectors? cups? washers? plugged fuel filters? Something else?
Here are some pictures of the last filter

 

Most would of had cups/injectors at least once, if not twice more, since 2015. Sorry for bad news, but you probably already knew what it was.