Diesel slime, big-time!

[difflock]

In a plastic tank, on a 1989  G Wagen, which is kept brimmed with diesel cos the fuel guage does not work.

Copious copious quantities of it too, but no water that I could see any evidence of, though perhaps the microbes "eat" the limited water.

Only my second experience in a life time of driving older diesel vechicles and tractors.

The other occassion was a one-off in the 1984 DB, back 10 or 15 year ago, where I simply cleaned the gauze in the lift pump and changed the filters and it never has re-occured.

[spuddog0507]

Just had a simular issue with a truck, steel tank tho and there was loads of a brown like jelly substance, we got some out the tank and left it in a jar and yes when we had that frost a few wk back it did freeze up,,we just drained the tank and put a camera in it and there was a substancial amount of what looked like brown frog spawn on the botton and sides of tank along with a fair bit of rust so just bought a new tank,,your plastic tank would steam clean out ok,,

[coppice cutter]

Our oil man says that since they went to low sulphur diesel you're asking for trouble if you buy any more than what you can use in a year.

 

I guess if you keep topping up you're never really fully replacing and refreshing it?

 

Might be part of the problem.

[waterbuoy]

The pronlem is worse though if you don't keep a full tank.  Moisture in the air gap condenses out onto the sides of the tank and run into the diesel.  The bacteria (ie the diesel bug) feed on the boundary layer between the water and diesel and, whilst it eventially starts off as resembling dark iron filings, quickly develops to form stringy, jelly like material which can block fuel lines and filters etc.  The most common blockage point on our boats fuel tanks is the pickup pipe, but if it gets past that then the CAV filter usually pritects the engine.

 

We ave suffered huge problems from the issue since the boats were able to return to work post Covid so now use fuel additives every fill which seems to have sorted out the problem.  Whilst we had to remove and clean three tanks in 2021, all of the tanks (predominantly plastic) were fine throughout 2022.

 

[difflock]

Our local motor factor actually suggested looking on Ebay for the additive, whilst nodding towards a litre container brought in special at £80.00 + VAT, which he said treated either 1000 litres or 1000 gallons.

[Stephen Blair]

Go to a marina/ boat shop they sell the additive to stop Algy forming in the tanks.  
 

edit, what Waterbuoy said! 

[Treewolf]

If you have a quantity of fuel which needs cleaning, Google for a "fuel polisher" in your area. He'll turn up with a van containing a pump, some clean drums, and a load of fancy filters, and filter your bug-filled diesel until it is clean. It's a common job on boats, so especially if you are near the coast or a waterway there'll be someone not far away. It's cheaper than disposing of the fuel.

 

I had this done to the fuel from my Defender some years ago when the bug got in and it was horrifying how much crud was in the fuel.

[Steven P]

I'm with coppice cutter, experience of the past means I regularly let the tank get to it's last litre before filling up - stops the muck accumulating.

 

Not sure what the cost and effort of a clean is and what the cost and effort to fit a new fuel gauge? You'll know. Failing that looking at the what MPG do you get thread, might be worth doing a few sums to figure what a tank should get and run it to 3/4 empty more regularly?

Edited February 18, 2023 by Steven P

[coppice cutter]

10 hours ago, waterbuoy said:

The problem is worse though if you don't keep a full tank.  Moisture in the air gap condenses out onto the sides of the tank and run into the diesel.  The bacteria (ie the diesel bug) feed on the boundary layer between the water and diesel and, whilst it eventually starts off as resembling dark iron filings, quickly develops to form stringy, jelly like material which can block fuel lines and filters etc. 

Yes that's a fair point too.

 

I guess when there was a higher sulphur content in the diesel it inhibited the bacterial growth in the first place, which is what sulphur does (also why excessive amounts of processed food are so bad for your digestive system).

 

So limiting moisture availability, which bacteria also need, should help as well.

 

We haven't had any trouble in any of the tractors yet, but they're usually run pretty low then filled, diesel storage tanks the same.

 

Have to say though, if I were having trouble I'd tend to look towards either an additive or reduce the amount purchased at a time.

 

Ironically the same decisions as we're now having to make with petrol.

 

Progress! 

Edited February 18, 2023 by coppice cutter

[Whoppa Choppa]

Best we've found. And boy do we get some sludge. It's nothing to do with Sulphur, but biodiesel content

Edited February 18, 2023 by Whoppa Choppa