# Diesel use by date



## Chascass (May 10, 2007)

A lot of vans will be ether used very little or not at all over the winter months other than may be a sort run out now and again to keep brakes etc from deteriorating.

My van at the moment has a full tank of diesel and got to thinking dose it have a use by date before it starts to deteriorate.

I'm only referring to the diesel in the tank that may be there for months, not what may be in the engine that should be replaced with a short run out. 

Charlie


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## Techno100 (May 8, 2010)

If it has have no fear the van will have rotted away long before :wink:


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## Jezport (Jun 19, 2008)

Cant offer help here but I know unleaded petrol goes off quite quickly, thats why a lot of generators have problems at the start of the season.


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## PincherM (Jul 28, 2011)

Charlie

I had a boat and the recommendation was to always fill the tank up with diesel for the winter to stop condensation.

Vic


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## spatz1 (May 19, 2011)

you should always park your van up with a full tank to prevent condensation in the empty space of the tank which collects and fills the water trap in the fuel filter when the van is used.....
As reguarding old diesel, the lighter "elements" tend to evaporate off over time which actually increases the cetane rating of the diesel .... which increases power.
Anyone who has lived abroad and drawn diesel from the bottom of a 25 year old diesel domestic heating system tank will tell you its like bolting a second turbo to your vehicle as the power increase is staggering....They ll also tell you it blocks the fuel filters very quickly !!!


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## Jezport (Jun 19, 2008)

Just read up on it,

Diesel can absorb water over time, so a tank is best kept full. Bacteria and other nasties can grow in it which are not good. 

Maybe an additive that stops the bacterial growth can be added.


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## Penquin (Oct 15, 2007)

I came across this answer to that question (which surprised me totally);

_Diesel fuel does have a shelf life, but can be extended by adding fuel preservatives. With the preservatives, life expectancy is about 2 years maximum. Fuel oil tanks can be purchased used rather cheaply, as they are often replaced when converting home heating units to propane or natural gas.

The down side of diesel, is that it has a limited use. Either for heating or for running your diesel engine equipment. If you purchase bulk quantities of diesel fuel, make sure you are going to use it within that 2 year period. Diesel fuel can be affected by bacteria, and is affected by direct sunlight._

http://answers.yahoo.com/question/index?qid=20070520141147AAUJhiI

It appears that bacterial action can cause problems, which may clog filters etc......

Now we know (if we trust them)......... :?

Dave


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## Wilmannie (Feb 7, 2010)

Also, of course, it's wise consider the financial implications! Your money earns next to no interest in the bank and the tankful of fuel might cost twice as much by the springtime!!


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## Chascass (May 10, 2007)

Wilmannie said:


> Also, of course, it's wise consider the financial implications! Your money earns next to no interest in the bank and the tankful of fuel might cost twice as much by the springtime!!


Spoken like a true Scotswoman :lol: :lol:........but true I had not thought of that.

Charlie


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## Spacerunner (Mar 18, 2006)

Jezport said:


> Just read up on it,
> 
> Diesel can absorb water over time, so a tank is best kept full. Bacteria and other nasties can grow in it which are not good.
> 
> Maybe an additive that stops the bacterial growth can be added.


Good service garages will include an additive to eliminate bacteria growth. Check your service invoice to make sure this has been done.


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## DTPCHEMICALS (Jul 24, 2006)

Sounds like good advice to keep the tank full.

But if I go out and use a gallon or two I don`t think I will top up that small amount.

Dave p


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## JohnsCrossMotorHomes (Jul 21, 2007)

Oh well I have been running my garden tractors and diggers on 20 year old gas oil (red diesel) it must have cost 10p a litre in those days and the machines run very well on them.

I do however strain the fuel before it goes into the tank.

I do not advocate running a vehicle engine on it, apart from it being red of course!

Peter


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## rogerblack (May 1, 2005)

Jezport said:


> Cant offer help here but I know unleaded petrol goes off quite quickly, thats why a lot of generators have problems at the start of the season.


I use a special fuel preservative/stabiliser additive made to prevent this on unleaded for my generator, outboard engine and garden power tools - add it to each 5 litre tank then it's already in and mixed in the correct ratios. Have left these engines with treated fuel in for months over the winter season and they've started first pull.

Regarding the diesel, do they still supply a different grade of diesel for winter months? Summer diesel used to have a problem with waxy fractions solidifying out if still used during cold winter months.


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## tony50 (Oct 16, 2007)

I can't see a problem apart from if you did change your mind and want to use it in winter and it's very cold the fuel could wax up preventing use , otherwise if you don't use it and the fuel waxes in the tank as soon as the weather changes from very cold the diesel will revert back to ok ,as said petrol will deterioate over time but that's a spirit diesel is an oil .

tony50


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## Stanner (Aug 17, 2006)

tony50 said:


> I can't see a problem apart from if you did change your mind and want to use it in winter and it's very cold the fuel could wax up preventing use , otherwise if you don't use it and the fuel waxes in the tank as soon as the weather changes from very cold the diesel will revert back to ok ,as said petrol will deteriorate over time but that's a spirit diesel is an oil .
> 
> tony50


Diesel bought in summer months does wax up quite quickly if the temperature drops below freezing. I've had it happen.


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## Codfinger (Jan 11, 2008)

For sure summer derv will wax up in cold temps, winter diesel has additive to prevent this. see post number 6 here http://www.mbclub.co.uk/forums/general-discussion/81419-iam-diesel-waxing.html


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## radar100 (Sep 8, 2010)

Having read the original post I must point out one misconception in it. Diesel engines continually circulate the fuel through the system sending unused fuel back to the tank, often, on modern engines, through an inline cooler, so the idea that a 'short run will use up the fuel in the engine' is completely wrong!


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## TR5 (Jun 6, 2007)

One problem that can occur is the moisture in the fuel causing corrosion in the fuel tank.
Not such a problem in many modern vehicles, as many tanks are now plastic, butcertainly in older vehicles, and especially petrol engined vehicles, as the ethanol additive causes moisture attraction into the fuel at a much higher rate.
Can be a worrying problem for classic owners, who use their cars only periodically, and leave fuel in the tank.

Back to diesel and waxing, the old solution was to add 5-10% petrol to the diesel to reduce the risk, but I am unsure how a modern common-rail diesel would cope with this, or whether it would be unwise to do so now.


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## Stanner (Aug 17, 2006)

radar100 said:


> Having read the original post I must point out one misconception in it. Diesel engines continually circulate the fuel through the system sending unused fuel back to the tank, often, on modern engines, through an inline cooler, so the idea that a 'short run will use up the fuel in the engine' is completely wrong!


It will clear out (either by combustion or by return to the tank) the fuel that has been sat in the injection system though and draw through some of the fuel that has been sat in the tank.

If the tank has been topped up by fresh fuel that will then be drawn into the injection system.


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## duxdeluxe (Sep 2, 2007)

The biggest problem with the diesel is moisture. Not only the obvious problem but with water, even in small quantities underneath the oil, which can result in the growth of anerobic bacteria, causing sludge and blocked filters. It probably won't happen with Peter's 20 year old gas oil but with modern pump fuel the bacteria just love the compulsory bio components. 

As diesel oil is a middle distillate cut from a refinery, the evaporation is somewhat minimal. Leaving the tank full is a very good idea but the water issue is a question of risk management - sometimes it will happen sometimes not. By coincidence, one of the programmes I am currently developing for my company (piloting it in Germany) is a winter "yacht service" where we test various bits including the fuel stored and the engine lubes; the former as above, the latter to check the health of the engine. Interesting, but quite small project


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## tony50 (Oct 16, 2007)

Stanner said:


> tony50 said:
> 
> 
> > I can't see a problem apart from if you did change your mind and want to use it in winter and it's very cold the fuel could wax up preventing use , otherwise if you don't use it and the fuel waxes in the tank as soon as the weather changes from very cold the diesel will revert back to ok ,as said petrol will deteriorate over time but that's a spirit diesel is an oil .
> ...


so have I several times

Tony50


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## rogher (Dec 17, 2006)

I had a boat powered by diesel that I didn't use for six years. The tank was full and had an additive to prevent diesel bugs. When I came to start up agaim, everything worked fine. Just as well, because there was a lot of diesel in that tank!
Roger


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