15 replies to this topic

[mab01uk]

After 3 months winter break without a run had to drain replace my stale fuel at the weekend as it will never start on it in recent years after 3-6 months.........new fuel in tank and SU and it fired up first time.

Interesting write up on shelf life of modern petrol here:
"The gradual elimination of Sulphur from fuel (not well publicised) has resulted in a lower shelf life for unleaded fuel. Oil companies surveyed estimated that a half full tank of unleaded could be unusable in as little as 2 months. Sulphur used to be added as a preservative to slow down algae growth in the fuel. Without it, the algae grow and the fuel quality deteriorates. How old is the fuel in your tank now?"

So yesterday, I phoned the BP Technical Support Line, and asked about the shelf life of unleaded fuel. “One month” I was told. “After one month in a half full fuel tank (ie: unsealed, plenty of air space) you would notice a drop in power. After three months, the car would be hard to start, would not idle well, and would suffer a significant loss of power. By this time, much of the high volatility elements in the fuel will have evaporated, leaving the more dense part of the mixture. In addition, the fuel will be oxidising and fungus will be growing. The fuel takes on an orange colour and gets progressively darker as time goes by.”
More:
http://www.spriteparts.com.au/tech/fuel.html

[jaydee]

I think in one month of shelf life we should consider the storage times before it reaches the fuel tank..i've noticed the drop just after 1/2 weeks on the rally car

[Mini Mad Drakeley]

if you have a car which you drive on nice days just during the summer then you will probably have to replace the fuel before its even been used? seems like its just away to rip people off

if you were to buy a bag of sulphur could you just add a wee bit to the fuel if you dont use it that often to help preserve it?

[Alex_B]

Last time i checked you couldn't buy a bag of sulphur at the local tesco and i doubt you could just dissolve some

[cagy]

And there was me thinking it had a shelf life of 6 months...

[patto]

We have just taken the boat out of storage for this year and my dad for the second time running has forgotten to run it dry before putting it away . So for the secons time running im the one that has to clean all the fuel lines out and strip the carbs down because the fuel has turned to jelly , that was in just over 4 months

[mab01uk]

I have been recommended this works on the MCR forum:

POR15 Fuel Preservative & Stabilizer
http://www.frost.co....er-us-pint.html

Edited by mab01uk, 15 March 2012 - 07:23 PM.

[puggered]

Personally I think its all just mince. I have shell unleaded fuel in my Marina and its been sat for 3 years and still STARTS!

[mab01uk]

Personally I think its all just mince. I have shell unleaded fuel in my Marina and its been sat for 3 years and still STARTS!

It is not 'mince' I am not imagining this...........it happens to mine and others I know with cars and little used classic motor bikes have the same problem, 3 years ago your fuel is unlikely to be the same make up as that on sale now maybe. The more sealed the fuel system is from the air the better, it lasts alot longer in a fuel injected car for this reason.

Quote:
"The gradual elimination of Sulphur from fuel (not well publicised) has resulted in a lower shelf life for unleaded fuel. Oil companies surveyed estimated that a half full tank of unleaded could be unusable in as little as 2 months. Sulphur used to be added as a preservative to slow down algae growth in the fuel. Without it, the algae grow and the fuel quality deteriorates."

Edited by mab01uk, 15 March 2012 - 10:55 PM.

[twrminisport]

Personally I think its all just mince. I have shell unleaded fuel in my Marina and its been sat for 3 years and still STARTS!

It is not 'mince' I am not imagining this...........it happens to mine and others I know with cars and little used classic motor bikes have the same problem, 3 years ago your fuel is unlikely to be the same make up as that on sale now maybe. The more sealed the fuel system is from the air the better, it lasts alot longer in a fuel injected car for this reason.

Quote:
"The gradual elimination of Sulphur from fuel (not well publicised) has resulted in a lower shelf life for unleaded fuel. Oil companies surveyed estimated that a half full tank of unleaded could be unusable in as little as 2 months. Sulphur used to be added as a preservative to slow down algae growth in the fuel. Without it, the algae grow and the fuel quality deteriorates."

To be honest i think this is mince also.
Even if the car/bike will not start all you have to do is drain it out from the float bowl and it will go on the stuff in the tank (old cars and bikes) as the stuff in the float bowl goes of alot quicker.

I put old petrol in my mini and morris minor on a regular basis because i tend to get hold of a lot of it through my dad's motorbike shop where the customer wants new fuel.
Reality is the bike starts up on the old stuff 9 times out of 10. I have also never had a problem with it in my mini

Jesus

[bugs42]

i know someone who used to work for shell, and apparently the fuel would lose an octane every week, so on standard unleaded that would be 83 octane after 3 months.

[R1minimagic]

Have they never heard of biocides or anti-oxidants? Of course they have!!

You have to use a bit of common sense here.....obviously the useable life of any fuel depends on how it is stored....temperature, exposure to sunlight, water contamination, what type of storage tanks are used, contamination with other fuels (they all go down the same pipeline!!), and gets mixed with various other fuel in storage tanks even before it gets to you etc etc etc

So it is impossible for an oil company to state an exact shelf life but they have to state something so they say 1 month. In fact they also state 1 month for biodiesel which degrades a lot faster than gasoline, so that tells you something straight away!!

Modern vehicles have much better fueling systems which are not so exposed to the environment so you can expect the fuel to last much longer than in an older vehicle....

[njathind]

Well theres a dribble left in my MPI tank, been sat for 2 years. Will let you all know how I get on.

[puggered]

I still think its mince. I started up the Marina this morning and the last fill up was in January 2009 at my local shell garage. The car has sat in the driveway exposed to the elements of mother nature for the last 3 years and if what folk in here are saying then my car shouldn't start but it does....

[mingy]

I would not dispose of the "stale" fuel if you only have a small amount in the tank,just fill afew jerrycans with fresh unleaded fuel and mix it with the existing fuel and go on a good tootle about.
I work for a company that manufactures aviation fuel storage facilities and we store upto 18,000 litres of a certain type of aviation fuel (Jet1A).
So long as we keep it in an airtight environment it will keep for quite a while without degrading,but there are additives that we can introduce to most fuels that keep it fresh and free from bacterial growth which only causes problems when a certain amount of water/condensation is present in the storage facility.
As we all know,all forms of life need water to survive and the bacteria live where the fuel lays ontop of the water. Anyway less of work, just mix and drive.