Old Diesel, use it or throw it?

[hullabaloo]

we bought a boat that had been on dry land for three years, how do we no if the diesel (half full) in the tanks is good or bad,
do we;
1; drain and throw it away.
2; start the engines and see what happens
or
3; drain it and give to someone we don't like.

if it's drain, do we have to get the last drop out?

 

[Mike k]

I think its one of those questions that its difficult to answer with any certainty and for me the decision would depend on the volume at stake - of its <20 gallon, I would drain it all. My boat had 60 gallons of 18 months old diesel when I bought her and was fine BUT was full. Petrol goes off quicker than diesel and on the plus side for diesel my old tractor has coped with very old diesel.

Could you take a sample and get it tested somewhere?

 

[hullabaloo]

Could you take a sample and get it tested somewhere?

arrrr i can see where this is going ! you want 30 gallon for you tractor.

 

[oldgit]

Depends on quantity.If only a couple of gallons might be worth dumping but nobody should be considering wasting 20 or more gallons of perfectly usable diesel.Provided it is perfectly clean and not contaminated,would simply dilute with fresh fuel.My boat had been lying unused for several years.
When bought boat back home visually checked tank for any crud and added equal amount of new fuel.Changed filters before departure and carried 2 further sets for both engines.
Probably more vital if you are using your boat offshore rather than on a river.

 

[Mike k]

arrrr i can see where this is going ! you want 30 gallon for you tractor.

haha not at all............20 is ok!!

Seriously its about risk and cost, for a few gallon is just not worth it especially if you are going coastal!! If its half full and plenty of it then as Oldgit says new fuel will help condition it and that's ok especially if you are pootling around river or lake with easy access safe havens.

 

[rafiki_]

Diesel does not go off, so if it is clean, and free of the bug, then use it, or donate it to us.

 

[david_bagshaw]

If you are not happy with keeping it pass it this way!

However I have used diesel that was over 10 years old , with no ill effects. Admittedly on old tech engines.

 

[hullabaloo]

free of the bug,

how do you know if there is diesel bug?

 

[nimbusgb]

Black or dark brown 'goo' in the filters or the tank if you can see in.

Google 'diesel bug'

 

[Bandit]

No real info given by op?

Quantity of diesel in question.

Type of engine , old mechanical or electronic common rail.

One or two engines.

Appearance of fuel and pre filters clean and clear or lumpy and ****ty?

You could inspect and test for diesel bug with a test kit, however appearance first and sampling from the bottom of the tank.

 

[hullabaloo]

i think i have my answers in the last two post,

i will suck some out , put it in a glass, if it looks like the images on google i will buy a test kit (which i did not no existed).
thanks

 

[Bandit]

You don't answer any of the questions ?

Before use check a sample preferably from the bottom of the tank.

Look at it is it clear, does it smell bad?

What is the content of the remote mounted pre filters like assuming it has been run recently, if its a Racor type pull the element and inspect the contents, is there water in the bowl, if its a sealed steel cartridge cut the end off with a hacksaw and inspect the filter element.

You don't say whether its common rail engines if so much more expensive to repair if you ingest ****ty diesel?

You don't say whether you have 20 gallons or 250 gallons if the former bin it clean tank and start from scratch, if the latter treat with a good biocide at shock dosage such as Grotamar 82 mix in a can of half a gallon of diesel and tip into your tank and leave for a week or two to let it do its work then have the fuel remotely filtered and returned to the tank.

Use biocide in the future as a preventative every time you fuel and always carry 3 sets of prefilters on board in case of pulling through fuel bug when at sea.

I would use a jam jar rather than a glass or your G&T will never taste the same again from that glass.

 

[hartcjhart]

Depends on quantity.If only a couple of gallons might be worth dumping but nobody should be considering wasting 20 or more gallons of perfectly usable diesel.Provided it is perfectly clean and not contaminated,would simply dilute with fresh fuel.My boat had been lying unused for several years.
When bought boat back home visually checked tank for any crud and added equal amount of new fuel.Changed filters before departure and carried 2 further sets for both engines.
Probably more vital if you are using your boat offshore rather than on a river.

and where do you suggest 'dumping' it??, if it is a few gallons and sh11ty keep it for future use as a de-greaser,or give it to a local garage/marina for said use

 

[Bandit]

If its a small ammount its probably not worthwhile making a filtration unit or calling in a contractor so get the old stuff recycled. I assume filtration contractors charge a minimum charge which would probably be more than the replacement cost of the diesel. If there are other bonafide uses for the old stuff then great.

Then you can get on with cleaning out the tank of remnants, water and crud and put new diesel in and treat it with a biocide so job done.

 

[Trundlebug]

An easy way to tell how contaminated it is is by the colour.

The darker it is, and the harder to see through, the more moisture and dirt there is.
If it's light red and transparent, it's very clean.
If you rig up a simple fuel polishing kit you can easily clean it up and make it like new with no wastage at all.

As said above, make sure any sample you take is from the bottom.
That's where any water will be, and any black gunge (bug and bug deposits).

I would be quite surprised if there's no bug at all after a long period of time, so be prepared.

Note that even if you stick in some fuel treatment (e.g., Grotamar as described above) that won't get rid of the black gunge already there. It'll just prevent more from being formed.
The best action by far is to filter (polish) the crud out of it, and remove the moisture, then add fuel treatment as a final measure.

 

[Trundlebug]

and where do you suggest 'dumping' it??, if it is a few gallons and sh11ty keep it for future use as a de-greaser,or give it to a local garage/marina for said use

Our marina, and all waste disposal facilities have a waste oil storage tank. Any waste diesel can be safely disposed of in there.

 

[alanorion]

A half filled tank will attract condensation. I bought a boat in Australia with about 20 gallons left in the tank I am unsure how long the tank had been left without filling to the

brim. I have a pump with a five litre capacity in the holding tank and got out well over a gallon of water from the bottom of the tank. I then paid for a tank drain and clean to

remove all contaminants. A diesel engine fails usually from fuel supply in the majority of cases. This is why it is essential to fill a diesel tank to the brim especially over a winter

period.

I have had similar problems sailing in England. I have always been very cautious after a friend drifted up and down the Bristol channel with fuel problems in a twin screw

power boat. Both engines came from the same fuel supply and the filters had been placed in the wrong position in the fuel line. He escaped unscathed luckily .

In summary it is worth getting a pump and removing the bottom inch or two once in a while checking for water and subsequent diesel bug. I hope my thoughts are useful

Best wishes Alan

 

[pheran]

When I was faced with a similar situation, I wasn't prepared to take the risk. So I pumped it out, took it home, strained it though a few pairs of Madams old tights then mixed it with the 28sec. oil in the domestic storage tank. The CH boiler had no problems 'digesting' it!

 

[gordmac]

I got given a quantity of diesel a couple of years ago, old and buggy. Dosed it with Marine 16 and added cetane booster stuff for good measure. Engines ran fine on it and no problems with the filters.

 

[DieselPolisher]

I run a company specializing in fuel polishing and would suggest you bin the diesel. Diesel left for long periods almost always contract diesel bug. The Diesel bug then feeds on the hydrocarbon in the fuel rendering it less combustible. Also the organism excretes acidic waste which renders the fuel highly acidic which has been shown to be corrosive to the fuel tank, fuel lines, metal surface etc. No amount of fuel polishing will remedy the long term affects of diesel bug.