Contaminated diesel

[richg]

Hi
I found contaminated diesel in the filter housing and as the fuel level was quite low decided to empty the tank. As you know this has a 'hump' in the base where it crosses the hump in the floor.I seem to remember on the old Mk1 that jacking on the near side to what seemed an unsafe height caused any residual fuel to transfer to the right hand side where the take off pipe is located.It this the best way to do it? I can't remember whether I raised the car evenly front and back or simply raised the left side rear?

Rich g

[Birotor]

The micro biological contamination grows in the water in fuel tanks - not in the diesel. If you don't get it killed in the tank AND fuel lines you will have the problem for ever. Both condensation in the tank and entrained water in 'new' fuel will keep it growing unless you kill it. This is a mega problem in the leisure boat industry. Lots of advice on the net....

[MULLEY]

I've got some special fluid that you put in your tank to kill off the fungus, it only cost about £12 for a bottle which does a fair few tankfulls. Fingers crossed you can get it sorted cheaply & easily.

Just out of interest, how does water actually get into the tank? Is it just condensation overtime & surely as the fuel empties out of the tank during use, doesn't the water come out at the same time?

[Way2go]

Just out of interest, how does water actually get into the tank? Is it just condensation overtime & surely as the fuel empties out of the tank during use, doesn't the water come out at the same time?

Mulley, there is a small water content in the fuel and as oil is lighter than water this can separate and accumulate at the bottom of the tank. The tank take off is usually above the lowest point but clearly if sufficient water accumulated this would give its own problems even without bacteria.

On bacteria etc.........

Filter plugging can have several causes and often critical consequences. For example, low temperatures can cause wax crystallization, which can lead to fuel filter plugging. An example would be using untreated summer diesel fuel in cold weather. Wax or paraffin is part of the diesel fuel.

Contaminant build up resulting from excessive microbial growth and bio-degradation of diesel fuel can cause fuel filter plugging. Micro-organisms, bacteria and enzyme activity, fungus, yeast and mold cause diesel fuel degradation and the formation of waste products. The process is similar to milk turning into cottage cheese, a different form of milk. Of all the microbial debris and waste products in the diesel fuel tank only about .01% is "bugs". Even though microbes may cause and accelerate the process of fuel degradation, it should be clear that the waste products clogging your filter are not the microbes but fuel components which have formed solids

[kiwi]

Interesting topic

Might this explain why when I first got the TXD down to a low level the indicator light would not come on? (Not that that happens often) and also could it explain why I manged to run out with 6 litres still in the tank? ok I was climbing a small incline at the time (no not a mountain road ) and had had the indicating signs of loss of power several kilometres beforehand.


Another thought!!! You guys love throwing in a bit of bio fuel now and again I would take that as a place for the water to come from?

[Birotor]

What kiwi had is typical and unlikely to be life threatening! What is very different is the yacht that finds itself on a lee shore with a blocked fuel system. No one is saying it is the bugs blocking the filter it is the black flocculent result which doesn't alter the fact that the CAUSE is the bugs. Certainly on the Costa del Sol the presence of water contaminated with mbc in the tanks of garages and marinas is endemic. The increased addition of Ethanol in fuels is not helping.

[kiwi]

Not life threatening? It is when you got a long walk to the service station and you maths say you should have made it on what you had in the tank.....lol

You reminded me of the fantastic fuel blends I am sure NZ got experimented with before it went to the international markets. Few years ago there was a spate of seal failures resulting from a new batch of diesel being sold on the market about the same time the bio fuel mixtures come out. Some the nasties in modern fuel is quite scarey.

[MULLEY]

Sounds like if you don't regularly run your tank very low, then there is the potential for water to build up & then you're screwed.

[Birotor]

Kiwi I thought you colonials were fit chaps!

[Defender110]

Sounds like if you don't regularly run your tank very low, then there is the potential for water to build up & then you're screwed.

Or there is the theory of keeping you're tank topped up stops internal condensation in you're fuel tank preventing water contaminating the fuel.

[MULLEY]

Good point Kevan, no idea tbh, i just run mine down to fumes & haven't suffered any issues yet.

[kiwi]

Kiwi I thought you colonials were fit chaps!

Distance is distance no matter where you live the differance is 4 million people v 60 million in the same area of land

btw, I dont regard myself as a colonial just another pommie migrant apparently.

[kiwi]

Sounds like if you don't regularly run your tank very low, then there is the potential for water to build up & then you're screwed.

Or there is the theory of keeping you're tank topped up stops internal condensation in you're fuel tank preventing water contaminating the fuel.

I have forgotten how many times I have heard this and follow this advice. One the reason it states in the Diesel servicing to drain the Fuel Filter to remove water, that water must come from somewhere and is likely to be building up in your tank.

[MULLEY]

Either i'm blind or haven't noticed, never seen water in either of my diesels. Does anyone regularly find any when they change their fuel filter as part of a service?

[Defender110]

No not generally with a regularly maintained car run on forecourt UK diesel which is usually of a high quality delivered and stored in clean tanks / tankers. There are often problems with continental diesel which isn't always upto standard or well stored. I have also had lots of water contamination in plant and marine engines where the red diesel is sometimes of dubious quality and has been badly stored in already contaminated storage containers and drums. 45 gallon drums are the worst thing ever for storing diesel as they are often left stood up whith the top lip full of water with the tops submerged in water which gets sucked into the drums past the cap seals as they expand and contract with the temperature changes through the day. Plus modern plastic tanks on cars are not as vulnerable to condensation as older steel tanks which are still often used in plant and marine operations, including above ground storage tanks.