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eddie g · 03-19-2017, 03:43 PM

I had the same problem in my 2001 Diplomat, about 2,000 miles on filters, same black specks. I drained the fuel tank and found pretty much no water. In my infinite wisdom I decided that I was not going to continue and I would remove the tank. That's a job I will not tackle again. Got the tank out and cut 2 12"x12" holes in the top of the tank. Not what I expected to see, the top 2/3 of the tank was like new but the bottom 1/3 was rusting and had a thick layer of what could best be described as mud in the bottom. The main pickup tube was slightly above the crud but probley picked up some crud when on rough roads. This made me remember a time when i had a blow out on the trailer and I pulled over on the rumble strips on the side of the freeway at 50 mph. Within 40 miles the warning light was on. I think that the frequency of the vibration caused the crud to stir up to the pick up tube. I cleaned the tank then sanded all the rust spots, then a through degreasing followed by an acid wash. I used a chemical proof tank sealer, patched the inspection holes and reinstalled, problem solved. The tank had 2 baffles that went across the tank stopping about 4" short of the other side. 1 was backwards from the other so that sloshing fuel would have to make a S turn through the tank. Diesel fuel has contaminates that settle out over time (fill a 5 gal. Home Depot bucket with fresh fuel, put the top on and let it sit for a month then carefully remove the top and gently pour the fuel into something until there is about an inch or two remaining. Then you can see what settles out in a short time in only 5 gallons. I did this when I changed out the sending unit and was surprised by it.) I think the mud in my tank was a combination of this and the rust from the tank. It didn't come out easily, had to scrape it out with a putty knife. Maybe some kind of industrial strength degreaser followed by an acid wash with some type of agitation would clean it out. That is if you have the same problem. I saw no evidence of some kind of alge.

Jeff753 · 03-19-2017, 05:07 PM

Quote:

Originally Posted by eddie g

I had the same problem in my 2001 Diplomat, about 2,000 miles on filters, same black specks. I drained the fuel tank and found pretty much no water. In my infinite wisdom I decided that I was not going to continue and I would remove the tank. That's a job I will not tackle again. Got the tank out and cut 2 12"x12" holes in the top of the tank. Not what I expected to see, the top 2/3 of the tank was like new but the bottom 1/3 was rusting and had a thick layer of what could best be described as mud in the bottom. The main pickup tube was slightly above the crud but probley picked up some crud when on rough roads. This made me remember a time when i had a blow out on the trailer and I pulled over on the rumble strips on the side of the freeway at 50 mph. Within 40 miles the warning light was on. I think that the frequency of the vibration caused the crud to stir up to the pick up tube. I cleaned the tank then sanded all the rust spots, then a through degreasing followed by an acid wash. I used a chemical proof tank sealer, patched the inspection holes and reinstalled, problem solved. The tank had 2 baffles that went across the tank stopping about 4" short of the other side. 1 was backwards from the other so that sloshing fuel would have to make a S turn through the tank. Diesel fuel has contaminates that settle out over time (fill a 5 gal. Home Depot bucket with fresh fuel, put the top on and let it sit for a month then carefully remove the top and gently pour the fuel into something until there is about an inch or two remaining. Then you can see what settles out in a short time in only 5 gallons. I did this when I changed out the sending unit and was surprised by it.) I think the mud in my tank was a combination of this and the rust from the tank. It didn't come out easily, had to scrape it out with a putty knife. Maybe some kind of industrial strength degreaser followed by an acid wash with some type of agitation would clean it out. That is if you have the same problem. I saw no evidence of some kind of alge.

Just curious what did the baffles look like? Was it a 118 gallon tank? Would you like to do it again?

RustyTools · 03-19-2017, 05:10 PM

After sitting for 2 1/2 years (my health problems), I had to have a local marine fuel-polishing outfit come and do my tank ('06 Endeavor) due to algae growth. I'd toyed around with making a system myself before calling them, but when they showed-up with a pump system that took up pretty-much the entire back of a full-size van, I knew I'd ever equal their set-up.

The guys were really up-front about what happened and what it would take to 'cure the problem' and how I could prevent it in the future. Kinda surprising, because they were telling me everything I needed to do to keep them from coming out again.

Their best recommendations were to keep using an algaecide, refuel from a station that gets lots of traffic, and don't let the fuel sit long in the tank.

Pretty simple, really.

By the way, good write-up 'eddie-g'. Thanks!

Traveler2162 · 03-20-2017, 07:11 AM

Quote:

Originally Posted by RustyTools

Their best recommendations were to keep using an algaecide, refuel from a station that gets lots of traffic, and don't let the fuel sit long in the tank.

Ahmen!

Jeff753 · 03-20-2017, 09:05 AM

Quote:

Originally Posted by RustyTools

After sitting for 2 1/2 years (my health problems), I had to have a local marine fuel-polishing outfit come and do my tank ('06 Endeavor) due to algae growth. I'd toyed around with making a system myself before calling them, but when they showed-up with a pump system that took up pretty-much the entire back of a full-size van, I knew I'd ever equal their set-up.

The guys were really up-front about what happened and what it would take to 'cure the problem' and how I could prevent it in the future. Kinda surprising, because they were telling me everything I needed to do to keep them from coming out again.

Their best recommendations were to keep using an algaecide, refuel from a station that gets lots of traffic, and don't let the fuel sit long in the tank.

Pretty simple, really.

By the way, good write-up 'eddie-g'. Thanks!

Where did you have this done and roughly how much?

Jeff
2001 Dynasty Regent tag axle
Cummins 350 8.3 ISC
2012 Jeep Grand Cherokee Overland
FMCA ENERGIZED Task Force Chairman

firedoc · 03-20-2017, 10:48 AM

Interesting thread:

Where does this leave us volunteers that typically go to a site and sit for several months and then drive 100s or thousands of miles and then sit at another site for several months.
Use good fuel, sit with full tank, use biobor (when?), and get filters changed yearly. Anything else?
This thread has got me concerned.

garbonz · 03-20-2017, 01:10 PM

Quote:

Originally Posted by firedoc

Interesting thread:

Where does this leave us volunteers that typically go to a site and sit for several months and then drive 100s or thousands of miles and then sit at another site for several months.
Use good fuel, sit with full tank, use biobor (when?), and get filters changed yearly. Anything else?
This thread has got me concerned.

Get a 5th wheel and drive the tow vehicle, problem solved. LOL

eddie g · 03-20-2017, 03:01 PM

Mine was a 100 gal tank. The tank is a smooth metal box about 42" side to side, 54" front to back and 20ish"deep. The baffels are a smooth metal wall that runs side to side approx evenly spaced front to back. This creates basically 3 compartments. The front baffels starts on the right and stops short of the left wall by about 4 inches then the rear baffels starts on the left wall and stop 4" short of the right wall. I f you could imagine looking down on a maze there would be 3 rooms, if you start in the front room you would walk to the far left wall and there is a passage to the center room then walk to the far right and there is a passage to the rear compartment. These measurement are approximate from memory but should be the same design. The biggest problem is removing and reinstalling the tank and at 62 I probably would not tackle another. If you don't want to tackle the job then I would find a shop that would. It's not rocket science, just hard dirty work. The reason I decided to try this was when I drained the tank and got almost no water and debris s I knew something was going on inside the tank. I did not expect to see the rust as diesel fuel is pretty greasy.

Jeff753 · 03-20-2017, 07:11 PM

Thanks. Got it. I did find a plug covered with undercoating on the bottom of the tank.
Changed my fuel filters today and while the Nashville Cummins tech did use the new center o ring he also left the old one. I don't know if this double stack of gaskets caused the bowl to get debris in it or not. Cut open the primary and it was black but not totally plugged. Secondary fuel was still pretty clean. Didn't cut that one open though.
Will keep an eye on the bowl and if it gets dirty I'll change it again.
I may try to stick a tube in the full neck and take a sample. Hard to get to the bottom though.

RustyTools · 03-20-2017, 07:58 PM

To answer Jeff753's question...
We are in the Fl Keys with a plethora of boat-repair places in the area that have the equipment/experience to do 'fuel-polishing'. Basically they use a very high-volume powerful pump & filter to run whatever's in the tank repeatedly thru the cycle over a period of several hours. Then treat it with the algaecide. I think the polishing was about $250, but I also had other stuff done at the same time.

HTH.

RustyTools · 03-20-2017, 08:02 PM

firedoc -
Good question there. That's what got us in the situation in the first place, sitting with a full tank. I was told by my fix-it folks that algaecide/biocide was the ticket - as long as we can keep the bugs out we should be good.

Probably be good to not sit for months with a full tank in any case too, but that's just MHO.

RustyTools · 03-20-2017, 08:06 PM

I'm guessing 'garbonz' thought he had something useful to add, but not sure what it was or how it pertained to this discussion. Thanks anyway.

Traveler2162 · 03-21-2017, 07:55 AM

Quote:

Originally Posted by firedoc

Interesting thread:

Use good fuel, sit with full tank, use biobor (when?), and get filters changed yearly. Anything else?

Sitting with a full tank is not a good idea either. Diesel starts to break down pretty quickly with the asphaltenes starting to come out. If you open an old diesel tank and you might see that the inside appears to be covered in a kind of tarry sludge. This is the diesel breaking down.

No easy answers.

Empty tank means new air gets in tank as temp changes and possibility of condensation. ( I think but am not sure this is more an issue in cold weather areas

Full tank means no condensation in tank because there is no air transfer.

Full tank means diesel fuel is getting old.

I do believe that the best thing you can do is buy fuel from a reputable high volume station.

If you are going to have a full tank I think you need to use fuel conditioners

Here is a link that discusses water issues further.

Viewing a thread - Water absorbing device for diesel fuel tank