I noticed a fuel leak from my fuel filter cap and I changed the gasket with another bevel shaped one. That fixed the leak for the time being.

Before I put the gasket and cap back on I removed the filter and the picture shows the condition. The pre-filter is brown, and I changed it about 5K miles ago. Is this something that indicates an issue? With that many miles, is this normal to be brown, not black.

 

Wow! Makes me think that its getting oil some how.

 

Might want to compare with post #'s 34 and 39 here:

https://www.ford-trucks.com/forums/1...estions-3.html

If your tank is plastic, it shouldn't be rust. But it could be bacteria or algae.

If the fuel system in our heads really follows a one-way path to a dead-end in the heads (i.e., a "dead head") then it shouldn't be oil. And how oil could get even further upstream to your (frame rail ?) pre-filter is beyond me.

So, time to drop the tank and look for bateria or algae?

 

My tank is plastic. First thought was that it was oil, but wouldn't it be black? Algae would be green, correct?

 

I don't think in-tank algae could be green. Green requires sunlight.

PM Gary E in the thread I linked for you. From the pictures he posted in that link, it looks like the same color as yours. I believe he determined it was algae:

"yeah it has to be algae, I saw more pics of it being the same color too. The tank will come out and be scrubbed no use wondering when it will cause a problem. There really is no other way to get the bacteria and water out."

From "What does the algae look like when you cut open the old fuel filter?" :

http://www.justanswer.com/car/70vm5-...-old-fuel.html

"Algae growth in diesel fuel will stain the fuel a brown color like tea. You can also have a brown sediment that settles to the bottom of the fuel sample. See picture below. Taking a sample of fuel before the filter will help you to determine if there is any algae growth in your fuel"

 

Thanks, Tim. Does the tank have to be pulled, scrubbed, and cleaned or can I just add some biocide?

 

If you do decide to pull the tank, take a look at your brake lines that hide behind the tank. Mine were rusted bad.

 

Tact: Dang! I don't know that answer. But I do know that every time I try to cut corners and don't listen to the little voice in my head about what I really should do, that I personally get bitten in the butt.

I guess you could put in biocide in your tank, could buy a box of filters, and then run gallons of diesel through those filters hoping to catch all the algae in your fuel tank.

But that seems like an inefficient way to clean your tank...

And while driving to filter out that crap you would be risking fuel starvation to your injectors.

And apparently that little piston which compresses the fuel in the injector body hates to run without sufficient fuel as lubrication.

While at the same time hoping that none of that crap makes it by those filters to get stuck in those really, really, really small seven holes in each of your injector nozzles thereby ruining your fuel injection atomization and spray pattern.

I will say this. If you haven't done the Hutch Mod already, then drop the tank for sure and do it (and the Harpoon Mod) because your in-tank screens (and maybe your pickup foot screen) are undoubtedly just as clogged up...

I mean your fuel tank has been used for over 10 years and not had even one cleaning, right? Would you let your truck's other fluid resevoirs go that long without a cleaning?

We flush our radiators, our brake reservoirs, our transmissions, our power steering fluid, and drain our engine oil through the bottom of the resevoir. But we never think about the crap which could collect in the bottom of our fuel tanks over 10 or more years...



("Little Voice" out.)
Sorry Tact, my "Little Voice" can sometimes be a bit of a smart ***...

 

You also don't keep the same fuel in the tank for 10 years.... I don't see anybody removing their oil pan just to spray it out with brake cleaner every 10 years.

 

Hey MisterCMK: We both know that you know more about this stuff than I ever will. But Tact obviously has a problem which might actually benefit from dropping his fuel tank and cleaning it out...

And I would agree with you that we should in fact drop our oil pans and clean them up with brake cleaner at least every 10 years if we filled up with oil at every tom dick and harry service station once a week and if our oil pans (like our fuel tanks) didn't have a drain plug.

Just sayin'...

P.S. I experienced the bad results of the clogged in-tank fuel foot pickup, clogged in-tank screens, and clogged in-valley fuel water separator filter (although with a steel tank and caused by delamination not algae) and I am still really grumpy about it.

 

Tim's logic makes some sense to me. And doing a thorough cleaning of anything is never a bad idea, unless you know for sure it's totally unnecessary.