Shelf life of gasoline being tampered with?

[Tyler883]

I heard from an unreliable source that gasoline is getting an additive put into it to reduce it's shelf life. The guy was telling me that it is designed to discourage independant stockpiles of gasoline.

Instead of the 2 year shelf life, appearanlty is now closer to 3 months.

It might be a coincidance, but I've had bad gas problems with every one of my seasonal motors( ice auger, snow blower, motorcycle, chainsaw, generator, and ATV. I know shit just happens sometimes, but I've had machinery for close to 20 years and never had any problems with them until recently.

Anyway, like I said, I heard this from an unreliable source, can anyone from the oil and gas industry back up this story?

[FiveFreshFish]

I always thought gasoline only has a shelf life of a few months to maybe a year at most. But I never had any problems with my seasonal equipment whether it's 4-cycle or 2-cycle.

[TheBenzo]

Ive researched this a bit further and will say that your source is dry. Sometimes gasoline will sit in the tanks underground for more than two months without being cycled in some of the less busy stations. Cant be 2 month shelf life.

[Billet]

Originally posted by Tyler883
I heard from an unreliable source that gasoline is getting an additive put into it to reduce it's shelf life. The guy was telling me that it is designed to discourage independant stockpiles of gasoline.

Instead of the 2 year shelf life, appearanlty is now closer to 3 months.

It might be a coincidance, but I've had bad gas problems with every one of my seasonal motors( ice auger, snow blower, motorcycle, chainsaw, generator, and ATV. I know shit just happens sometimes, but I've had machinery for close to 20 years and never had any problems with them until recently.

Anyway, like I said, I heard this from an unreliable source, can anyone from the oil and gas industry back up this story?

talk to any old-timer and he will tell you that exact thing!!

farmers realize this better than anyone!

[Xtrema]

This guys sounds like what he's talking about:

Gasoline has a limited shelf life for several reasons.

Loss of volatiles - many gasolines have a lot of octane in the front
end ( very volatile fraction ), losing the volatiles lowers the fuel
octane. Loss of volatile front end octane can damage older engines
with carbs and no knock sensors, especially under intense
acceleration. It's not such a problem with modern auto engines,
but other small engine might have problems. Loss of volatiles also
cause hard starting on cold engines, and only gasoline vapour will
burn, not liquid.

Instability of the hydrocarbon fraction, particularly olefins (
alkenes, arenes ), the fuel stability treatment is designed to be
stable for 4- 6 months. As retail fuels in many parts of the world are
seaonally adjusted, diesel for cold flow, gasoline for volatility (
more volatile in winter to help starting, and less volatile in summer
to prevent vapour lock in older carbs, small engines, etc. ), there's
no reason to go for longer stability.

The olefin fraction is the major cause of gums, and also deposits
buidling up in the engine manifolds and back of valves. Engines with
fuel injection often recirculate the fuel, and the fuel can get quite
warm, so stability is still an issue for many modern FI engines .

Instability in the additives. Oil companies add enough additives to
meet the stability and performance requirements at the time of
manufacture and expected retail life. Some of those additives are
expected to react with exposed metals, rogue fuel breakdown products,
etc etc, and may form insoluble precipitates or gums. Other additives,
eg lead, oxygenates, MMT etc, are added to meet octance requirements,
and may also have other effects, such as changing the fuel lifetime.

Gum and deposit formation occurs rapidly once inhibitors have be used
up, and may be catalysed by traces of fine rust or bare metal
surfaces, warm temperatures, light, presence of water, etc. etc..
Storing gasoline is a very hit and miss exercise, even when
additional storage stabilizers have been added, because it depends
on the original formulation and additives as well as the storage
conditions. Once gums have formed, they do not redissolve into
a fresh tank of fuel, so prevention is preferred.

Oil companies do not like retail outlets to have low turnover of
any fuel, and may require outlets to maintain a turnover rate in each
fuel tank so they can provide seasonal fuels as required.

>> > Ok, so what kind of shelf life is it reasonable to expect?
>> Figure six months, max. Maybe a little more if you add stabiliser.

Depends on the ambient temperature, and the additive package of the
fuel, storage life in winter is usually longer than in summer, Six
months is a sensible maximum for winter, summer should be 3-4 months
maximum. For engines with recirculating gasoline and fuel injection, I
would reduce those times to 3 months maximum. Sure the engine will
adjust as best it can for low octane fuel, but why bother when it's
relatively easy to avoid.

>I once had a car laid up for 4 years. Made no special effort to preserve the
>fuel. On restarting it ran fine on the stuff that had lain in the tank all
>that time. New cars are often stored for months without a fuel problem.

So, feel happy, but I've dealt with customer complaints where their
fuel formed gums after 3 months, and the gums blocked the carb
jets. Not certain about the US, But new cars used to be given just a
couple of gallons of fuel with that had extra stabilisers to ensure
all active surfaces in the fuel system, especially those subjected to
vapour and condensation were inhibited and didn't corrode. Military
fuels and tropical fuels also have more stringent stability
reuirements, and often have additives to prolong storage stability.

OE fuel was also expected to last for 6 months storage regardless of
ambient May not be used now with polymeric fuel systems and fuel
injection systems, but I suspect that some OE fills still have extra
stability if the manufacturer expects to stockpile or ship the
vehicles long distances..

[Tyler883]

Here's an interesting link

http://theepicenter.com/tow021799.html

" The problem begins with today's modern fuels. These so-called "clean" fuels typically deteriorate at much faster rates than fuels made 20 years ago. While all fuels suffer from the problem, most at risk are the EPA mandated reformulated gasolines (RFG) that contain oxygenate additives, derivatives of methyl alcohol and ethyl alcohol. We've seen gasoline have shelf life as little as a month--particularly if it is subjected to heat and moisture.

Diesel fuels fare a little better, but not much. Most all diesel fuel, including the EPA's mandated low sulfur version, has shelf life of from 3-to-6 months. Again, this varies widely. Recently we tracked a diesel fuel produced at a refinery in Texas to its final destination in Florida. When tested at the refinery the same day it was produced, the fuel barely met the specification for stability. After being stored, pumped into a coastal tanker, offloaded at Port Everglades, stored again, delivered to the fuel jobber, and finally to the customer, 23 days had passed. Again the fuel was tested. This "fresh" fuel now tested out of "spec."

In part, this has to do with new processing techniques developed by refiners in recent years. While the new refining methods are more efficient, producing more gasoline per barrel of crude, these fuels are often far less stable than the conventional "straight run" fuels we had before.

To make matters worse, the quality of the crude oil feedstock going into the refinery changes daily with each shipment. Processing equipment must be precisely adjusted to these varying qualities, but it doesn't always happen. This neglect results in poorly processed, less stable fuels. One oil company survey indicates that at least 50 percent of the gasoline sold today is substandard.

Oxygenated fuels are also less fuel efficient, giving a minimum drop in fuel economy of 3 percent (if you believe the major oil companie--much higher if you listen to those among us who are fuel misers and check mpg regularly.) Additionally, there is strong evidence that these fuels pose dire health and environmental consequences. Public interest groups have assembled a large amount of data on the damaging effects of oxygenated fuels. "