Mud in Fuel Tank - Cat 301.8C

[Urban Digger]

This is a great forum. The information here has helped me fix a lot of problems over the past few years.

A few years ago, we picked up a 2008 CAT 301.8C to do some projects around the property. When I got it, it had low power and would stall. We replaced all the fuel lines and filters and put in a new lift pump. When we did this the screen at the bottom of the fuel pick up in the tank was clogged and we cleaned it.

After that everything worked fine for over a year and about a hundred hours on it. The problem came back. We found the screen was clogged again, cleaned it, repeat. We did this a couple of times and it was no big deal for a yearly task.

Now the screen in the tank clogs after about a half hour of use. Whatever was in the tank that would make its way to the fuel pick-up over time broke loose and is now floating around in the tank and a big headache. It looks like mud.

What’s the best way to clean the tank without removing it from the chassis? If there is a drain plug, we did not find it. The only access into the tank appears to be from the top where the fuel pick-up mounts.

Any help or pointers would be appreciated.

 

[Vetech63]

If you don't want to pull the tank, then the only way I know of is to rig up a shop vac and go through the top.

 

[Delmer]

Use a suck bucket: https://www.heavyequipmentforums.com/threads/the-suck-bucket.20354/

Park it on an angle so the fuel goes to one corner if possible. Suck the fuel out, let the fuel settle, put the clean fuel up high like on top of the cab with a heavy piece of steel or rock in the bucket so you don't tip it over, siphon the fuel back into the tank a gallon at a time rinsing the sides and bottom and then sucking out. May still have to repeat in a year.

I'll bet that stuff is from bio diesel that gunked up the walls, now another "hot" batch of bio has loosened it up. You can either live with it, or run off a 5 gallon plastic tank that stays fresher and cleaner.

 

[CM1995]

I'm with Delmer. Probably algae.

Had a Bobcat T250 that we ran some bio-diesel in that gave us fits with algae. Takes a a lot of flushing and filters to finally get rid of it.

OP I would take the tank off and clean it. Then have extra fuel filters on hand.

 

[Urban Digger]

Algae? Interesting. I'll research this. Can you tell by looking at it? The screen is clogged again right now. I'll pull it and take a picture.

I like the suck bucket idea. It would be useful for several different things.

My only apprehension to pulling the tank is the how much stuff that needs to come apart to get to it.

Thanks for all the input!

 

[CM1995]

Algae is pretty common with dirty diesel or biodiesel in my experience. Your first pic looks like algae to me but I could be wrong.

If you don't want to remove the tank (understand why we have a 305) you can shop vac the tank then buy commercially available products to kill it but once dead it will still clog filters until it's all dead and all out of the system. It's going to take a minute to get it all out.

 

[Nige]

Fuel algae was around long before biodiesel was even a glint in some fuel chemist's eye, although it appears to have become more of an issue with biodiesel. @Coaldust could probably give you chapter and verse on what causes it and how to treat it. Technically-speaking it's not algae because algae requires sunlight for growth and of course it's dark inside a fuel tank. It's more of a biomass bug that feeds on the hydrocarbons in the fuel and produces the visible sludge as a by-product. Back before the end of the last century these orgnaisms were often referred to as "humbugs".

Diesel Bug 101 - What Is It? How To Avoid It

A practical guide to identifying and getting rid of diesel bug, with links to the latest diesel bug test kits.

conidia.com

 

[Welder Dave]

If you have an air compressor you can make a suction as well. Make a T or a Y like an engine cleaner gun except use a larger dia. suction hose. The air going past the T will create a suction on the hose off the T and you can spray the air and liquid into a bucket.

 

[Coaldust]

That does look microbial. I say you have multi-generational families of Hydrocarbon Utilizing Microorganisms (HUM BUGs) eating your hydrocarbons and pooping.

That sludge is their poop. Don’t believe me? Look it up. We commonly call it algae, but it’s not algae. It’s poop.

 

[Welder Dave]

It would be pretty accurate to say the fuel tank is fill of $hit.

 

[Tugger2]

Fuel bacteria was our nemesis in the marine construction business .Lots of large fuel tanks ,hot fuel return from Detroit diesels = condensation which seemed to accelerate the bacteria.We used a product called Biobore which killed off the bugs and left a pile of muck . Next problem came from shaking up the fuel in the tanks ,being on tugs and barges it could happen a lot. We ended up with big Raccor filters as the primary ,they had cross over valves so you could swing from one filter to the other without shutting down. Some of our tanks had hatches so we could muck them out.
An air diaphram pump worked best for handling this stuff,you might be able to rent a small one for cleaning your tank.But as suggested above there are a few ways to suck this stuff out,id suggest you do what you can to shake it up a bit with minimum fuel in it just before you pump it .
I always thought this was just a marine related problem,

 

[Nige]

multi-generational families of Hydrocarbon Utilizing Microorganisms (HUM BUGs) eating your hydrocarbons and pooping.

The first time I came across Humbugs was in a 200k-gallon diesel storage tank (one of 3 on the site) in the dim & distant past. Hence my comment that they were around long before biodiesel. You can imagine the chaos it caused to the fleet that was being supplied by fuel from that tank. The good part about it was that the contracted fuel supplier (are you listening @Coaldust .?) was reponsible for tank maintenance, not us. All we had to do was deal with the fallout on a fleet of 60 or so machines........

 

[Welder Dave]

With a compressor you could put a hose in the fuel to agitate it. If you made a suction gun just block the end the air comes out and it will blow air down the suction hose.

 

[Coaldust]

The first time I came across Humbugs was in a 200k-gallon diesel storage tank (one of 3 on the site) in the dim & distant past. Hence my comment that they were around long before biodiesel. You can imagine the chaos it caused to the fleet that was being supplied by fuel from that tank. The good part about it was that the contracted fuel supplier (are you listening @Coaldust .?) was reponsible for tank maintenance, not us. All we had to do was deal with the fallout on a fleet of 60 or so machines........

I hear ya. 200k would be a nightmare. Wow.

I don’t run into very often. Usually, it’s imported from somewhere else in a machine. I don’t know if it’s the climate or we just don’t have the specific HUM bacteria present.

Years ago, I was preparing a presentation on HUM and dug into the early history. I found it was military aviation in the 50’s that seriously started researching and documenting it. The early formulations of distilled jet- based fuels were especially problematic.

 

[Coaldust]

One of the common and specific HUM strains is worrisome to people, pseudomonas. I haven’t found any research linking transmission to people from handling contaminated fuel. But still, I do take more precautions to avoid skin contact and breathing vapors when cleaning a tank with “algae “ in it.

Same bacteria that causes “ hot tub syndrome’ , or folliculitis.