Old Gas

[Tobygot]

Hi, I have an Expedition in my garage that has a half tank of gas (14 gallons)that will be 4 months old next week. I live in AZ were it's about 110 degrees everyday (118 last Saturday), so my garage is probably 140-150 (no vent).

The battery died and it hasn't been driven for a couple of weeks and it will be another month until I can buy a new battery.

Should I add 5 gallons of gas with Stabil or siphon out the gas?

Thanks

 

[EricF]

the 4 month old gas probably lost 1 or 2 octane points if that.
I honestly wouldn't worry about it at all.
If you want to save, it, adding the fuel stabilizer NOW will keep the octane level where it currently is. It will not increase it back up. you'll have to add an octane booster to that gas to kick it up a notch.

If anything, just add more gas and drive the truck around.
Nothing will happen if you just drive with what's in there now.

 

[Mr Nice]

I would add 5 gallons to top off the tank so moisture doesn't build up. 4 month old gas is still OK for me not to worry about it.

Why haven't you driven it on a regular basis ?

 

[Tobygot]

Gas is too expensive for me. I have a Saturn that gets twice the mpg's, so the Expedition was driven about once a week (7 to 10 mile drives) until the battery died.

 

[fdcg27]

When you put it back into use, just fill the tank.
No harm done, and I doubt the fuel in it has lost octane.
Always best to store a vehicle with a full tank to reduce condensation.
The alcohol found in nearly every gasoline will take care of the water, though.

 

[Tobygot]

15 years ago I took a college biology class where I had a lab partner who claimed to work for a gas or oil company (I don't remember which).
She told me that gas started to grow a layer of mold on top of it after only about 3 weeks. This is why I figured my gas must be really bad.

 

[eljefino]

I had a truck with gas that routinely got... just that old! I had august gas in december. What's funny is the Reid Vapor Pressure was totally wrong so I had to give it a little gas to start and it was a little wonky until it warmed up.

I was driving four miles round trip to the dump twice a month.

 

[bullwinkle]

Originally Posted By: Tobygot
15 years ago I took a college biology class where I had a lab partner who claimed to work for a gas or oil company (I don't remember which).
She told me that gas started to grow a layer of mold on top of it after only about 3 weeks. This is why I figured my gas must be really bad.
Are you sure they weren't talking about diesel fuel (although technically it would be mold on the BOTTOM)? Gasoline wouldn't be a very good medium to grow anything in, it just loses it's more volatile (i.e. explosive) elements and turns to varnish.

 

[Digital2k2]

Would gas lose octane faster on a lower tank due to the larger air space in the tank?

 

[Torino]

Run it! John--Las Vegas

 

[friendly_jacek]

One word: stabil!
it works for up to 1-2 years. I use it in a boat that sees 1-2 uses a year. Never failed to start.

 

[Digital2k2]

I let it go regularly a few months and once at least 6 months in my old truck. Never noticed it run any different.
It might be better fill it up when you start to get down to half a tank if you routinely go that long between fill ups.

Also maybe add some MMO? It's supposed to help stabilize fuel and doesn't cost much.

 

[Boss302fan]

Just curious, does Stabil go bad if it sits on the shelf for a few years?

 

[Quest]

Stabil package instructions on the back sez that it's good up to 2 years after opening.

I tend to use them up before 2yrs, and/or give them to some friends for their small engines and perhaps cars before they expire.

 

[Bamaro]

4 months is far from old

 

[steve20]

4 months under those conditions is old--if it werer sitting in a shaded garage in New England I would think differently.
As the fuel system is (should be ) sealed probably not a huge problem. Add Stabil at 2X the recommended amount-get the new battery in-and run that gas down as empty as you dare. If it is going to be sitting again, I would add just keep 5 gallons in it at a time, and add Stabil to every tank if these 'sitting' conditions are going to continue

 

[Durango]

Toby,

Generally speaking if you gonna keep you gas that long you should fill it up all the way!!!! This way you keep as much air out of the tank as possible cuz air is what breaks down you gas.

My next door neighbor is retired and only uses her car for groceries etc. and only fills the tank when it's needed. After a couple months goes by her car starts to blow smoke out of the tail pipe so you know after that time the whole tank is spotted.

Durango