Gas shelf life

[Michael D]

My truck has sat for over a year with a nearly full tank of 91 octane.
So I was planning to purge the tank low enough to get rid of bout 90% of the current gas and refill it with new but do I really need to?
How long does 91 octane or any really last. There is no humidity here in Az which helps.

I'm asking because I recently learned we have a place in town that will take old gas for free. Ha, that's a business I should look into.
It will be road worthy very soon and that old gas running through the fuel system and the possibility of screwing up something has been on my mind.
FWIW, the gas is feeding an injected LS LQ9, not carburated.

[dmjlambert]

Do you have a daily driver you can put it in and burn it 5 gallons at a time mixed with new gas? That's probably what I would do.

[Michael D]

Unfortunately no, diesel only.
I didn’t consider 5 gallons mixed with fresh gas. I may have someone(s) that can benefit, thanks for that suggestion.

[old51sedan]

I think about this with my truck, have had it back together for 3 years now, driving just up and down the road getting things adjusted, so it's had gas added a little at a time, but I have always added staybilt to it. That being said a few years ago I bought a used motorhome in Florida that had been setting for 5-6 years without being started, (paid $1.00) loaded with everything. Had a 454 injected, and the 80 gallon tank was full, but had stay built. Put new batteries in it, rolled it over a few times and it lit right up. I gave it to my granddaughter and her husband, they flew to Florida, put new tires on it and drove it to Michigan, stopping every so often adding fresh gas to it. They drove it everywhere for 3 years with no problem, last year they had it stored in an older building and it all burnt down. Ins. paid them 10 grand for it. Just something to think about.

[72c20customcamper]

Octane has nothing to do with shelf life . Ethonal will pull any moisture out of the air but living in AZ you probably wouldn’t have a problem with it. Here e10 will last a few months max in a vented system

[Michael D]

As I mentioned I live in Arizona and heck I don’t even use a fuel stabilizer in my boat or dirt bikes. I will say I can tell a difference in the boat the first couple hours on the water after letting it sit for several months. Add 70-80 gallons of fresh 91 octane and it runs like it should.
I’m just concerned it could gel in the lines or cause some other issues I haven’t even thought about so my thought was just be safe and dump it.

[LockDoc]

-
I would just run it out, adding fresh whenever you get low enough to do so. If you are just going to start it, and not drive it enough to run it out, I might think about draining it and putting fresh in it, otherwise I wouldn't worry about it.... Just my 2¢ worth.

[57taskforce]

I live in New Mexico. I have a ‘98 K2500 that I let sit for about 3 years without running it due to a transfer case leak that took me longer than I wish to get to. When it came time to start it back up I put a new battery in it and about 5 gallons of fresh fuel. The tank was about 1/2 full of old gas. I cranked it over and it started right up like it always does. The only issue I had until the old gas was burned off was the exhaust stunk pretty bad like old gas. Honestly after only a year I think you will be fine. You could always keep running it down 1/8 or 1/4 tank at a time and then top it off to full for a little bit till the old stuff is diluted out pretty heavily.

[Michael D]

Thanks gents, and yeah I know the smell you’re referring to from my boat but that gas never gets older than 6-7 months and it can burn through 80 gallons in a day and get fresh fuel.

[jumpsoffrock]

Originally Posted by Michael D

Thanks gents, and yeah I know the smell you’re referring to from my boat but that gas never gets older than 6-7 months and it can burn through 80 gallons in a day and get fresh fuel.

I would also like to support "not worrying about it".

I also live in a west coast dry area, and my brother had a modern fuel injected junk car in our backyard about 10 years ago. Randomly after 5 years I neded to move it just a few feet but I figured I'd try and start it. It never ran very well before--that's why it was parked. Nonetheless I put in 2-3 gallons of fresh fuel and it ran fine-ish.

I don't think gas deteriorates nearly as quickly as folks like to scream about. Also dry climates help too, for sure.

[MARKDTN]

I would pull a sample in a glass jar. If it looks like gas and smells like gas I would just run it. Maybe don't dog on it until the next tank.

['68OrangeSunshine]

I live in Tucson, AZ. I have about a dozen old school steel jerry cans. I buy in bulk at the end of the month using my *Fry's VIP points when I can get a Dollar a gallon off the pump price, with a 35 gallon limit. Most jerry cans are not used immediately so I spike them with STA-BIL fuel stabilizer. Two oz per 5 gallon can.
The manufacturer states you can store fuel for two years using their product. I've only found a can that old, that I skipped from rotation once or twice, but the gas burned OK.
I put a piece of green gaff tape near the neck of the can, and mark the Date/Brand/Octane Rating/Price/and Sta-Bil if added.
Unstabilized gas can be mixed with fresh gas if you have the empty jerrycans to play.

[* Fry's is in the Kroger network, including Smith's. Fred Meyer and others.]

[IIGW]

Originally Posted by Michael D

My truck has sat for over a year

what do you think we do when we get deployed overseas for a year or more?
think we drain the fuel from our cars?

no

we jump start the thing because the batteries are dead from sitting and then we go driving.

Thousands of us military personnel

Dont over think it.

just drive it.,

[Michael D]

Originally Posted by IIGW

what do you think we do when we get deployed overseas for a year or more?
think we drain the fuel from our cars?

no

we jump start the thing because the batteries are dead from sitting and then we go driving.

Thousands of us military personnel

Dont over think it.

just drive it.,

You're killing me Smalls.
I absolutely remember what I did each time I deployed. I found someone that wasn't and needed a car and sold it!
Bad gas, heck i could barely afford to fill the tanks back then. Wait... that hasn't changed much these days. LOL

[Michael D]

Originally Posted by '68OrangeSunshine

I live in Tucson, AZ. I have about a dozen old school steel jerry cans. I buy in bulk at the end of the month using my *Fry's VIP points when I can get a Dollar a gallon off the pump price, with a 35 gallon limit. Most jerry cans are not used immediately so I spike them with STA-BIL fuel stabilizer. Two oz per 5 gallon can.
The manufacturer states you can store fuel for two years using their product. I've only found a can that old, that I skipped from rotation once or twice, but the gas burned OK.
I put a piece of green gaff tape near the neck of the can, and mark the Date/Brand/Octane Rating/Price/and Sta-Bil if added.
Unstabilized gas can be mixed with fresh gas if you have the empty jerrycans to play.

[* Fry's is in the Kroger network, including Smith's. Fred Meyer and others.]

We dont have a Fry's here in Havasu and as for Fred Meyer, aren't the just in the PNW?

['68OrangeSunshine]

Originally Posted by Michael D

We dont have a Fry's here in Havasu and as for Fred Meyer, aren't they just in the PNW?

Last I saw one it was in Spokane, so yeah.
Kroger is nationwide, and has taken over a lot of regional grocery retailers.
KingSoopers/ Ralph's/Smith's/ Mariano's/Payless/ Dillon's/Food4Less/MetroMarket/ Pick'n'Save... A lot more.
Look up KrogerDOTcom.
I think they all have the VIP program. Riding shotgun with a friend this summer, we used my August 100 points for a buck off gas at Smith's in Vegas.
Good hunting.

['68OrangeSunshine]

Originally Posted by Michael D

You're killing me Smalls.
I absolutely remember what I did each time I deployed. I found someone that wasn't and needed a car and sold it!
Bad gas, heck i could barely afford to fill the tanks back then. Wait... that hasn't changed much these days. LOL

That's how my PO got the '68 C/10 Stepside. He was Army, but got ahold of the MCB Camp Pendleton base paper. A Navy Capt [O-6] placed an ''Orders overseas, need party to take over payments'' ad in the classifieds. So this guy a short Sgt. bought the truck off the Captain, who was a Catholic chaplain at CamPen. I was a civilian when I bought the truck, but enlisted myself shortly after.
I left the Stepside with my Dad. Who used it a bit in town. But the battery was flat when I got out of Boot, anyway.

[72c20customcamper]

Big difference between a modern vehicle and an older truck like owners . New vehicles are pretty much a sealed system so moisture isn’t a problem . Our vehicles vent and suck in atmosphere with every change in temps . Specially in the fall and spring around here temps can swing 40 plus degrees .

My new cars I’ve left for long periods of time and never had a problem . A few years ago I did a late road trip with my 77 Suburban and forgot I used e10 gas so I never added any stabil to it . Truck ran like poop when I took it out in the spring . Changed the filter and added new gas truck didn’t run well until the second fill up . Time frame was about 5 months . I use non E gas in all my older vehicles and power equipment prior to being available in my area I would have spreading carb issues in my mowers and chainsaws even with stabil . Haven’t had one issue in the past 6 years with the b non E gas.

[Michael D]

Originally Posted by '68OrangeSunshine

That's how my PO got the '68 C/10 Stepside. He was Army, but got ahold of the MCB Camp Pendleton base paper. A Navy Capt [O-6] placed an ''Orders overseas, need party to take over payments'' ad in the classifieds. So this guy a short Sgt. bought the truck off the Captain, who was a Catholic chaplain at CamPen. I was a civilian when I bought the truck, but enlisted myself shortly after.
I left the Stepside with my Dad. Who used it a bit in town. But the battery was flat when I got out of Boot, anyway.

The first truck I ever owned was given to me. It was my dad’s 72 custom deluxe long bed in grapefruit yellow and white.
It became my baby. My dad smoked at the time and I remember whipping out the inside and it turned yellow again, lol.
I’m former Navy and was in Hawaii for 2 weeks and when I came back my dad said I need to tell you something. Your brother, who was 16, took the keys to your truck, mind you my dads old truck, and ran a stop sign t boning a woman in a car.
My first question was… how bad is my truck? I was 19 and my dad said “I should slap the crap out of you, how bad is your truck???… Your brother is fine, in case you care”. At the time I didn’t care about him. That truck stayed parked for 3 years before I got enough money to get the frame straightened, a new front end, paint, etc.
From that point on I just sold everything other car I would buy except for the truck. I restored it and gave it back to my dad a couple years after that.
Less than year later he gave it to my brother who sold it and bought a Volkswagen Karman Ghia. Hahaha. Can’t make chit like that up. My brother has since passed and damn I sure do miss him.

[KQQL IT]

If mine sits for a month or more. Have to do power valves and accelerator pumps.

[BAD1916]

I have a friend that used to maintain a car collection and he would mix in race fuel on the cars that had been sitting a while. I honestly don’t know how long they sat or if the race fuel was necessary but it always worked for him.

['68OrangeSunshine]

Originally Posted by KQQL IT

If mine sits for a month or more. Have to do power valves and accelerator pumps.

That's why I quit Holleys 20 years ago.

[slikside]

Originally Posted by KQQL IT

If mine sits for a month or more. Have to do power valves and accelerator pumps.

I think it's a California thing contributing...ethanol doesn't age well, and you can't escape it here. But a month seems very short to me. I overhauled my quadrajet about 13 years ago with appropriate parts from Cliff Ruggles High Performance, and my truck can sit a good bit longer than that...now, it will have to crank for a while to get some fuel and compression to my tired old (original) 350, but once it fires the first time, it's running!

My lawnmower is a different animal though. I figured out several years back to never leave gas in the tank. I don't need to use it often, so I only put as much gas in it as I think I'll need, and when I'm done, I let it run itself out of gas (Just don't tell the CARB {California Air Resources Board...so ironic, can't make this stuff up!}). It can be months later before I need it again, but with fresh gas, proper priming and some starting fluid, it'll start on the first pull. If I have old fuel from the mower sitting around, I'll dump it into my truck and burn it. Never a problem there.

[Rust_never_sleeps]

Mine sits for long periods and I generally don't sweat it. Generally it sit's about 1/3 full, so Once I crank it up I'll add a few gallons of fresh. I try to remember to add stabilizer, but frequently don't
When I got it and it was pretty rank, I dumped some Berryman in there to keep the bowl from getting sticky. Smoky, but it seems to manage the dissolved solids OK

One time I got "clever" and sprayed carb cleaner right in the bowl, which immediately distorted the accelerator pump blue seal, so I don't do that anymore.