Old Gas Question

[shatto]

Originally Posted by trollbait

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.

I'll guess that the oil in the spark plug hole will do an adequate job of oiling the cylinder wall but there are two other considerations: As the letter to me from Amsoil said; any oil during combustion will cause carbon at the rings and on the piston and also (and also is the same as saying also, also or and, and, but I digress) it will not lubricate and protect the intake system, valves and parts of the cylinder above the piston run. Knowing Amsoil, the fogging oil is designed to burn off and not make crud.

[Jay2TheRescue]

My thoughts are that any little bit of oil burning off in the cylinder walls is nothing compared to the damage that rusted cylinder walls can do.

[theholycow]

A little squirt of engine oil in the cylinder once a year before storage isn't going to hurt anything.

Any brand of fogging oil, including Amsoil or whatever you find on the local shelf (such as PB Blaster LMT), ought to do fine for protecting the intake and cylinder. It's not rocket surgery.

[kit352]

Higher octane goes bad quicker. It also sits in the gasoline stations tanks longer since its so much more money than regular.
If i know a vehicle is going to be sitting for more than a month i'll dump some sta-bil in it. Ive never really had an issue with gas. I'll add dry gas into some of my more water pron tank like on the lawnmower thats left outside and some of my boats just to make sure water deposits arent an issue. Sta-bil is supposed to do that as well but its not as good as actual dry gas. I did some trials with odd gas i had around with water in it and the dry gas worked so much better and stayed working. The sta-bil absorbed it but fell out of solution within minutes. It looked like soda in reverse, All the bubbles falling to the bottom. I suppose if you keep it shaking it would be fine.

[trollbait]

Originally Posted by kit352

Higher octane goes bad quicker. It also sits in the gasoline stations tanks longer since its so much more money than regular.
If i know a vehicle is going to be sitting for more than a month i'll dump some sta-bil in it. Ive never really had an issue with gas. I'll add dry gas into some of my more water pron tank like on the lawnmower thats left outside and some of my boats just to make sure water deposits arent an issue. Sta-bil is supposed to do that as well but its not as good as actual dry gas. I did some trials with odd gas i had around with water in it and the dry gas worked so much better and stayed working. The sta-bil absorbed it but fell out of solution within minutes. It looked like soda in reverse, All the bubbles falling to the bottom. I suppose if you keep it shaking it would be fine.

You happen to know what alcohol the dry gas used? Depending on the amount of water, ethanol might be what the Sta-bil used. It worked at first but soon phase seperated. E10 alone should keep a fuel system dry of trace amounts of water. Too much water and the ethanol and water drop out.

Isopropanol is better because it isn't prone to that phase seperation. Of course, the dry gas may have simply had enough ethanol to overcome the phase seperation limit of that sample.

High octane gas may go bad quicker for an engine that requires high octane gas, but if the engine can run on 87 octane, then the premium fuel will last longer than regular. They are both losing 1 octane per month in your typical gas can.

[Project84]

I've always been of the understanding that gas is good for 6 months. I'm not sure if I ever read that, was told that, or just came to that conclusion by wrecking my first car and it sitting about 7 months and promptly firing up and running strangely on my 1-month warm ups at around month 5 or so.

It was an '84 Camaro with 87 octane in the tank. Honestly seemed about 5 months into sitting that when I'd go start it up (advice I got from my father - start it and let it warm once a month to keep things somewhat lubricated) that it started running a bit odd.

I religiously use Sta-Bil and SeaFoam both now days. I use Sta-bil in my fuel can for lawn equipment and for my Camaro and pickup truck that only get used about a thousand miles per year each. I purposely only fill the tanks halfway because they sit so much. Before storing them I first put the Stabil in the tank while nearly empty and drive it up to the gas station, fill 1/2 way, and drive it home, giving the Stabil plenty opportunity to mix all the way through the fuel system and new gas.

My daily driver gets SeaFoam in the tank once a year to give me the (perhaps false) impression that it's keeping things clean inside the tank/lines/injectors, never any Sta-bil because the car never sits more than a few days.

As for Engine Fogger- I have some and used it in a project Miata I had sitting for 2+ years. I'd spray inside the cylinders once every 6 months. I can't speak to the effectiveness because I sold the car before really driving it but the next owner got it running and never mentioned any oil burning/oil loss so I can only speculate the fogger helped keep the cylinder walls clean of rust and protected the rings on startup.

[Project84]

In recap - I use Sta-bil on stuff I know will sit 4-6 months or longer. Never had any issues. Stabil says it's good for 6 months I believe, and the bottle suggests adding it to new/fresh gas. Putting it in 6 months after the car has been sitting won't help much.

I use SeaFoam as a fuel system cleaner only. Never to store gas.

Honest - on higher compression engines that have sat 6+ months I've noticed a seat-of-the-pants driving difference in old gas vs fresh gas.

[trollbait]

The only time I've heard of old gas causing damage was with a friend's'75 Chrysler Newport. The gas had sat in the tank for ten years. The resulting gum build up bent push rods. He had no trouble starting it up though.