M925A2 Fuel Tank Algae?? Black tar substance on bottom of tank

[jwesley74]

Hi guys, I tried searching for any posts regarding this. I just picked up truck from LA and drove home to FL. It has black tar substance layered across bottom of tank. Filter canister had it too so I changed canister & filters, spin on and cartridge. I drained tank, hand wiped as much of gooey tar substance I could reach but it's still on other side of baffle. I'm told it's black algae. Anyone have luck cleaning there tank with same issue? Whats best method to clean it? I see the several biocide additives etc... I put a tank cleaner in before I drove it 1000 miles. Also put diesel 911. I ran about 180 gallons thru it trip home. Changed filter about 500 miles into trip. Truck runs better but still sluggish compared to my 923A2. When I did filter change it had the carmel tar like stuff in the new canister already. So it's sucking it up from the tank.

Also, due to this contamination I believe it may have clogged fuel check valves. It loses prime when it sits for few hrs. I have to put compressed air to tank and crack the fuel line by the rack to bleed air. Then starts right up. It takes hrs for it to lose prime, if I restart within couple hrs or so it's fine and fires right up. Any suggestions??

Thanks for any help!

 

[armytruck63]

What does the stuff smell like? A petroleum smell like tar or crude oil, or like rotten eggs? Do you see rust in the bottom of the tank?

You may want to pull all of the fuel lines and clean them in solvent. Probably should do this to the injector lines too. You could also pull the injectors themselves and have them cleaned and tested by a diesel engine shop.

It also could be that the truck sat for a time with the tank empty and this stuff could just be varnish left behind when the fuel evaporated.

 

[jwesley74]

Smells petroleum based. Super sticky/nasty. Almost like pine sap on the skin. I tried acetone, purple cleaner and brake cleaner. Nothing broke it down when I was trying to clean the filter canister. Which is why I just changed it with new one. So taking lines off and soaking in solvent is not an option at this point. I was told to drain tank, put gasoline in tank let soak. drain and let air dry for few days. If it's algae gasoline would kill it and with drying out. Then it should flake off. BUt wanted input from anyone that had similar issue and what they did.

Thanks.

 

[162tcat]

I had a similar problem in my boat. It's hard to clean out a 1200 gal tank so I just ran lots of additives and changed filters often. Not totally fixed yet but better. In your case, it might be easiest to just replace the tank. Lots of trucks are being parted out currently.

 

[jwesley74]

I had a similar problem in my boat. It's hard to clean out a 1200 gal tank so I just ran lots of additives and changed filters often. Not totally fixed yet but better. In your case, it might be easiest to just replace the tank. Lots of trucks are being parted out currently.

Yeah, changing tanks is the option I'm looking at. Found a tank in PA and a buddy is 90 miles away in NJ. He may go get it for me this wknd. Figured I'd spend more in chemicals/time to try to clean this one with who knows what kinda results. Also just realized theres an AFC filter in the pump, I just ordered to change that while I'm cleaning any check valves. It's clear the truck sat a long time.

 

[pctrans]

Gas seemed to work the best for me. Need to let it set for a day, then slosh the h3ll out of it (had to repeat a few times). Also had to take the fuel line off at the filter, plug the other end and filled it with brake cleaner, then blew it out with an air hose. Last step was to fill the filter cannister with injector cleaner. Has worked well since then.

 

[jwesley74]

Gas seemed to work the best for me. Need to let it set for a day, then slosh the h3ll out of it (had to repeat a few times). Also had to take the fuel line off at the filter, plug the other end and filled it with brake cleaner, then blew it out with an air hose. Last step was to fill the filter cannister with injector cleaner. Has worked well since then.

You have same black sludge on bottom of the tank? Most/all of it come out? Thanks for the suggestions.

 

[cj8scrambler]

Take a look at Algae x and their diesel fuel catalyst and magnetic fuel conditioner. We have used these on several boats with very good results.

 

[cx65083]

I've found that when it comes to dealing with diesel alge, there is no one time adding brand "X" product and being done with it. It is an on-going process to clear it up. Adding alge cleaner or anti-alge is a start. I've used the mixing gas with diesel with some success. Too much will hurt you're motor, so don't go overboard! I did it by running the tank low then adding 5-10gal. gas to the near empty tank and letting it sit. Then adding 20 gal. of fresh diesel to get it down the road a few miles to fill the tank. Ran like crap.
But always keep a filter in the truck and another on reserve. You WILL use them until your tank is clear!

 

[BKubu]

Take it to a professional shop and have them clean out your fuel system. I had the same problem with an M925A2 that was a military mechanic school truck and had 120 original miles on it. For a reasonable fee (I don't recall the exact amount, but I believe it was like $250), they cleaned everything out and I have not had a problem in more than two years. Or, you can screw around with it on your own to save $250 (or whatever your shop will charge). Doing stuff yourself is nice, but sometimes it makes sense to pay someone else to do it.

As a side note, the PowerService algaecide is expensive! Price it out.

 

[wreckerman893]

When I was stationed at Fort Benning back in the mid 80's we had four 900 series tractors that had the same problem and were a recurring source of annoyance because they constantly had clogged fuel filters.

We came to find out that there was an official notification about the situation (I think it was addressed in PM magazine). It seems that some of the tanks had an internal coating that was.......wait for it....wait for it.....soluble in diesel fuel. (never forget your
equipment was built by the lowest bidder)

We ended up taking the trucks to 3rd Shop maintenance and they removed the tanks and boiled them out. Problem solved.

 

[Captaincarrier]

Being in the fuel tank cleaning business, we see this everyday. Thick, black, greasy diesel fuel turned to sludge.

 

[Jeepsinker]

Wreckerman, that story is hilarious!

 

[jwesley74]

UPDATE, I took the advice of several and drained tank completely, poured 5 gal gasoline in, let sit for a day and drained agian. Filtered out large particles with coffee filter from gas, put back in tank and agitated with 2' stick thru holes in baffle to make sure all sludge was gone. During all this I also sprayed gasoline with pump up garden sprayer on entire inside of tank. Drained again, let air dry for 5 days and tank was spotless clean. Also ran gas thru supply line from primer pump to canister, cleaned canister with gasoline and put fresh diesel in with pint of Algae X in tank. Now onto another problem. Primer pump check valve had debris/algae in it. And primer hand pump started leaking after taking apart cleaning screen and check valve. So ordered new primer pump. Finally got to install new pump last night, pressurized tank, bled air out and started up. It idled for 20-30 minutes then would die. Lost prime. So prime it again. Repeated process 6-7 times. Gave up last night. Today, bled again, pressurized tank found small drip from elbow supply line into primer pump. Took elbow out, wrapped with teflon tape and no drips now. Bled system, starts up and runs. Now the puzzling problem. When engaged in gear it stalls. Cannot keep it running when engaged in gear. Even with rpm's up to 1000 and engaging it stalls. My buddy gave up for now, I'm working but will try to figure out when I get home this afternoon. 1st I'm going pull return line and inspect/clean check valve and verify its pumping fuel and no air in line on return side. Any other suggestions are appreciated.

 

[jwesley74]

Thanks everyone for help and input. As it turned out it was air still in the lines. Got it bled out, and drove the truck which worked out the rest of the air. Then turned the low fuel up 3 revolutions and governor up 3 clicks. Runs GREAT now. Actually idles where it was supposed to and better acceleration now. Starts up with a bump of the starter everytime too.

 

[MtnSnow]

Congrats!