Old Gas Question
 

Technical questions, if I may.

Christmas Eve eve, I was fired from my courier job.

My Tundra, which had been driven between 150 and 350 miles a day for 250,000 miles has been driven no more than a thousand miles since.
Which leads to the question; how long can petrol (gasoline) sit in the tank before it becomes stale, rotten, yucky or whatever happens when it goes bad?
And what to do about it, or better, prevent it?

Additionally, is there any reason to change from 25,000 mile oil changes?
I use AMSOIL SAE 0W-30 Signature Series 100% Synthetic Motor Oil with the Amsoil EA oil filter, both rated for 25,000 mile/one year between changes.

IDK, the gas in our van can get pretty old between fillups. We usually don't drive it more than a few hundred miles a year. We never have any problems with old gas. I try to remember to put Stabil in the tank when I buy gas, but I don't always remember to do it.

As far as the oil changes go, change it once a year.

A modern fuel injected vehicle doesn't care. I guess if a tank is going to last two years you might put in some Sta-Bil.

I know you're a big fan of Amsoil but if you're out of work you may want to cut your expenses and use a basic oil for your yearly oil change until your truck is back to earning its keep.

The octane can drop over time. That's one of the reasons the Volt uses premium. It is roughly lowers by 1 per month. The drop is likely slower in a modern vehicle's sealed fuel system though.

Sea Foam can be used as a fuel stabilizer, and you can mix your own Sea Foam for some cost savings. Check a can label, but IIRC it's 1 ounce per gallon. Sta-bil is probably easier, but if you need the Sae Foam for something else...

Michael,

Thank you for taking the time to contact AMSOIL with your questions.

Gasoline generally has a useful lifespan of up to 30 to 90 days. Without treating the gasoline, it can start to oxidize, separate, and/or form gummy varnish deposits that will cause poor engine performance. The AMSOIL Performance Improver (API) would be a good additive to use to keep the fuel system clean. If gasoline is going to be left in a tank for periods of more than 90 days (up to 1 year) it would be recommended to use the AMSOIL Gasoline Stabilizer (product code AST).

Engine oil drain intervals should be up to 1 year, if mileages are not going be approaching the 15,000 mile severe service interval, or 25,000 miles normal service intervals.

We hope this is helpful.

Darryn Wallace
Sr. Technical Service Representative

AMSOIL INC.
ADDRESS: 1101 Susquehanna Avenue, Superior, WI 54880
E-MAIL: dwallace@amsoil.com
PHONE: 715-399-8324
FAX: 715-392-3097

I'm a little bit curious. Our bikes rarely sit for such a long time, though this time we had an unusually snowy winter and Ciliegia (my girlfriend's bike) was sitting from November to April with the same tank of gas. After that 5 months we needed cleaning additive because it left deposits in the carbs that caused poor idling and acceleration.

Our other bike (Teresa, fuel log to the left) and car are fuel injected, so it must be somewhat different. But my car usage pattern surely makes the question relevant: I haven't started the YARDIS for at least a month now, and a full tank (filled up in May) is going to last until like october when we plan a longer car trip. That's 5 months again.

Fuel injected fuel systems are usually better sealed. That and topping off reduces the amount of air that contacts the fuel. Without air, the amount of oxidation is limited. In the case of carbs, some fuel is left in them. Being open the atmosphere for so long allowed the gas to evaporate. Leaving the heavier fractions, and any varnishes or gums that were safely dissolved, behind.

Adding fuel stabilizer or an injection cleaner won't hurt. If it is possible too, drain the carbs on the other bike before storing it.

I don't know because I don't and didn't store anything; but presumably a storage problem is rust, as on cylinder walls. Amsoil has a product for that: Engine Fogging Oil. Should work in Eastern Europe too. ;)

i picked up some "kohler" fuel stabilizer at tractor supply on clearance for 99 cents. not sure you have TS out in cali tho?...

You're supposed to squirt a little bit of oil through the spark plug port, and turn the crank to spread it out with lawn equipment before storing. I have never done this.

You want to fill a steel fuel tank up because of rusting.