Cloudy diesel

[jenevers]

I drained some diesel from the bottom of my tank into a plastic bottle and it’s still cloudy after several weeks. Normally water separates out and sinks to the bottom of the bottle, leaving clean diesel. Any ideas why?

Edited May 28, 2021 by jenevers

[Tracy D'arth]

28 minutes ago, jenevers said:

I drained some diesel from the bottom of my tank into a plastic bottle and it’s still cloudy after several weeks. Normally water separates out and sinks to the bottom of the bottle, leaving clean diesel. Any ideas why?

Fine sediment? Some of the diesel additives emulsify water and oil, perhaps it is a mixture of fuel and water but in the form of an emulsion?

[blackrose]

It's a bit like cloud cloudy cider, It's an acquired taste.

[Tony Brooks]

Have you been using any fuel additives and if so which one?

[bizzard]

I suppose there's a possibility that the fuel is attacking the plastic bottle.  Petrol is bad for that, not sure of diesel, depends what kind of plastic it is I reckon.

[Mad Harold]

43 minutes ago, bizzard said:

I suppose there's a possibility that the fuel is attacking the plastic bottle.  Petrol is bad for that, not sure of diesel, depends what kind of plastic it is I reckon.

If you use Fuel Set,it makes the diesel turn cloudy.

Used it in my last boat and the engine ran as rough as it always had.

[DandV]

I suspect the presence of detergent type additives that allow some emulsification.

Automotive diesel fuel suppliers routinely dose the fuel with some proprietary  additives to improve the cetane rating, lubricity, wax suppression, and some promoted, to keep injectors clean. I suspect that some of these may have some emulsifing properties.

Then there are multitude of aftermarket additives, promoted to keep diesel bug at bay, and other benifits. These primarily seem to consist of emulsifiers to disperse the water, and perhaps biocide. The fact they could impede water separation and thus the operation of conventional fuel water separators is the basis of my dislike for such additives.

I had much more trust in the fuel as supplied by major oil companies then fuel subsequently adulterated by customers.

In spite of any  additives added during distribution, saleable diesel fuel  should be clear and bright. The definition used by one international oil company was that normal print of The Times newspaper was readable through a Johnnie Walker bottle full of fuel. They did not provide the testing apparatus however or specify as to whether this feat should be accomplished after first drowning the original contents of the said bottle!

Edited May 28, 2021 by DandV

[jenevers]

12 hours ago, Tony Brooks said:

Have you been using any fuel additives and if so which one?

Yes. Marine 16

[Tony Brooks]

36 minutes ago, jenevers said:

Yes. Marine 16

 

Thanks, then if how I understand Marine 16 works its unlikely to be emulsified water unless you have used an emulsifier in the recent past.

 

FWFW A while ago I drew about 8 litres of very cloudy liquid from the bottom of the tank and left it to stand for nearly a month. A fair bit did separate but at least two litres remained as it was.

 

It is not unknown for suppliers to dose their bulk tanks so it might be an emmulsifier.

[Tracy D'arth]

Shoving unknown additives into fuel that is already dosed with something already from the bulk distributors is likely to produce odd results. If there is no water in the tank why do you want expensive additives?

[Bee]

Having had a big problem with water in fuel probably caused by a leaky filler cap I no longer use any additives at all. If there is any water in the fuel and there has not been for the last 4 years I can get rid of it with a pump. I am lucky enough to have an inspection plate in the tank though that I fitted and if I was designing or having a boat built I would stick that on the list of Very Important Things.

[Ex Brummie]

The only time I've had fuel problems was when bio content was introduced, I put in an additive. After a good clean out, I've not treated fuel .

[jenevers]

7 hours ago, Tracy D'arth said:

Shoving unknown additives into fuel that is already dosed with something already from the bulk distributors is likely to produce odd results. If there is no water in the tank why do you want expensive additives?

To avoid diesel bug.

[Alan de Enfield]

2 minutes ago, jenevers said:

To avoid diesel bug.

 

You dont get diesel bug without water.

The bug lives in the interface between the diesel and the water.

[Tracy D'arth]

3 minutes ago, jenevers said:

To avoid diesel bug.

If there is no water, there is no bug!

[jenevers]

22 hours ago, Alan de Enfield said:

 

You dont get diesel bug without water.

The bug lives in the interface between the diesel and the water.

Good point

22 hours ago, Tracy D'arth said:

If there is no water, there is no bug!

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