What is the life of petrol?

What is the life of petrol?

Author
Discussion

davidindevon

Original Poster:

223 posts

233 months

Sunday 22nd July 2012
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Hi all,
Basically does anyone know what the life of petrol is please?
It still looks and smells like petrol but I am wondering whether a gallon in the bottom of a tank is going to be usable after nine winter months or best to drain the dregs and start afresh.
Thanks.

crazyidea

109 posts

141 months

Sunday 22nd July 2012
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The petrol will have "gone off" by now but it depends on how much other gunk you have in your tank. The all build up sludge and sometimes it is best to leave it un-disturbed. I have always followed the advice to leave the car at least half full for a period where it will not move for a while and then top it up with the highest octane fuel that I can find (tes co have 100 octaine on some of their forcourts) doing the same a couple more times when the tank gets back to half full. Not sure if this works with a TVR engine but has done me well with MGs and historic Daimlers.

alex_gray255

6,313 posts

204 months

Sunday 22nd July 2012
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I believe two-three months at tops depending on type of petrol.

TVR500Morgan

1,183 posts

151 months

Sunday 22nd July 2012
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Modern petrol is 2 months tops from experience. Best thing to do is go and fill up a 20 liter fuel can with high octane fuel and it should be ok.

Lesliehedley

238 posts

259 months

Sunday 22nd July 2012
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My TVR has been SORN'ed for the past two years. I start the engine every month or so, but it hasn't moved more than a few feet in that time. The petrol is at least two years old. The tank is almost empty but it starts first time.

B19LAM

133 posts

154 months

Monday 23rd July 2012
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I can not believe some people on here think petrol goes off in 2 or three months , just goes to show you should never ever listen to the drible peddeled on places like this.

hurststeve

101 posts

198 months

Monday 23rd July 2012
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Petrol certainly does go off, but some engines are more sensitive to it than others. It wouldn't surprise me if most car engines would start and run fine on 9 month old petrol or even older. But a small two-stroke (such as my chainsaw) will not - will definitely not - start on three month old petrol.

RFC1

1,107 posts

196 months

Monday 23rd July 2012
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hurststeve said:
Petrol certainly does go off, but some engines are more sensitive to it than others. It wouldn't surprise me if most car engines would start and run fine on 9 month old petrol or even older. But a small two-stroke (such as my chainsaw) will not - will definitely not - start on three month old petrol.
Thats because its a 2 stroke, and after a while the petrol in the carb evaporates and leaves the oil behind which basically clogs the carb up.
Not the same as just "old" petrol.


My taimar starts and drives on 3 year old petrol.............

LordGrover

33,531 posts

211 months

Monday 23rd July 2012
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Doesn't it lose 1 RON a month or two or something? If you start out with 99 RON tesco's finest in about 6-12 months it'll be down to 'regular' 95 RON.

alex_gray255

6,313 posts

204 months

Monday 23rd July 2012
quotequote all
That helps. The 2-3 month figure was based on experiences of both neighbors who are avid bikers. Their petrol goes off after 2-3 months. I do know there are additives you can get to keep petrol good for upto 2 years, but def not my area of expertise. biggrin

hman

7,487 posts

193 months

Monday 23rd July 2012
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it certainly loses its poke after a few months

Geoff Ashcroft

351 posts

205 months

Monday 23rd July 2012
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[redacted]

Gazzab

21,061 posts

281 months

Dave_M

5,486 posts

223 months

Monday 23rd July 2012
quotequote all
Clearly it does not go off to an appreciable extent in a short period such as 3-6 months as there are many vehicles which are seldom used and these would have issues. It will degrade but not so much to impact us over such a small periodsmile

SharkyTVR

130 posts

210 months

Monday 23rd July 2012
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[redacted]

sjwb

550 posts

207 months

Monday 23rd July 2012
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I had this very conversation with a major gasoline refiner in relation to fuel left in portable fire pumps. The answer was, simply keep the tank FULL because the major cause of degradation is water. Gasoline is hygroscopic; reduce the exposure to air to prolong usefulness. The recommended term before discarding the fuel? Two to three years.

DonkeyApple

54,921 posts

168 months

Monday 23rd July 2012
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sjwb said:
I had this very conversation with a major gasoline refiner in relation to fuel left in portable fire pumps. The answer was, simply keep the tank FULL because the major cause of degradation is water. Gasoline is hygroscopic; reduce the exposure to air to prolong usefulness. The recommended term before discarding the fuel? Two to three years.
The ethanol content is, not the gasoline element.

Oxidisation is the real issue with stale fuel but this takes a long old time to actually be a problem. Keeping the tank full is the best way to slow oxidisation.

Barn finds in the past have been fired up on fuel that is decades old.

B19LAM

133 posts

154 months

Monday 23rd July 2012
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by stored right i mean in a container with a good lid, i have just worked on a car that was stood for 8 years and it started and ran fine on the fuel in it .

LordGrover

33,531 posts

211 months

Monday 23rd July 2012
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B19LAM said:
well over 2 years even longer if its stored right, bizzar that people just drop daft numbers like 2/3 months with no real idea what there taliking about, waht if the lad had taken that as being the correct answer, he would have wasted his time and money pissing around changing his fuel what a bunch of d--ks
Out of order. redcard
Make your point politely with good grace.

sjwb

550 posts

207 months

Monday 23rd July 2012
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The caveat regarding two to three years was not a statement as to how long fuel will last, more an assurance that a fire pump would indeed start when required!