OK to drive with old fuel?

[93Leg-c]

OK, I've searched but couldn't find an answer. Here's the question: Is it okay to drive an ss with fuel that's been sitting in the gas tank for a couple of years or more? Will driving the car easily till the fuel is used up damage any engine or fuel components in any way? If it is NOT good to drive the ss on that fuel, would you explain why, please? Thanks for your help, guys!

[vrg3]

A couple of years? Wow.

Gas that's been sitting for a couple years probably will not burn well at all in your engine. The first problem is that the really volatile parts of the fuel have evaporated away, leaving just the sludgy stuff that's hard to ignite. Another problem is that over time gasoline oxidizes into varnish that can clog the pump and/or the injectors. Finally, if the gas tank has been sitting for a year through heat and humidity cycles, there's probably a fair amount of water in the tank too.

Usually, the varnish is the only one of those things that'll really hurt anything. The water and sludginess will just make the engine run poorly (if it even runs at all) until you burn all the old fuel up. If you do decide to try burning this fuel, you can reduce the water problem by adding some isopropanol or ethanol to the tank.

My advice is not to even try. It's not all that hard to siphon the fuel out, especially if you have a jack so you can raise the driver's side high enough to get most of the fuel to pool in the passenger side of the tank. Then pour in as much fresh fuel as you can carry to the car, along with some of fuel system cleaner (like Techron or Seafoam), and gingerly drive to the nearest fuel station so you can top it up, diluting whatever old fuel remains as much as possible.

[93Leg-c]

Thanks, Vikash!

I heard that gas that has been sitting for quite some time in the fuel lines can turn into varnish and clog injectors. But I wasn't sure if driving the car would turn the existing gasoline into varnish as it made its way through the fuel system and engine.

My ss was driven to where it is parked right now about 16 months ago. Previous to that, it had been parked for a couple of years or so. When I started the car to drive it to where it is parked now, it started up right away and there were no problems in driving--no hesitation, no knocking, nor pinging. However, it was driven conservatively at about 40 mph or less for about 7 minutes with no hills to negotiate.

If I decide to drain the gas tank, where do I dispose of 15 gallons of gas? Yes, the tank is filled to the brim.

[mike-tracy]

I wouldn't run that old fuel in a turbo car, but I worked at a junkyard and we were allowed to fill up our cars once a week on all the old gas from the clunkers brought in.

So my 96 L ran that crap for about a year, and I got about 100 miles less per tankful than usual. When that job ended, I ran a couple full tanks of good gas with seafoam and then replaced the fuel filter - and the mileage went back to normal. 3 months on everything's still good with the 96.

Also my n/a 4runner sat for over a year when I was deployed and she started up, roughly and then was fine after the next tankful.

[evolutionmovement]

Fresh gas should clean out the varnish in the lines and such over time as well. Just plan on replacing a fuel filter or two.

[vrg3]

You have to dispose of the old fuel as hazardous materials. Everywhere I've lived, either the city or the county had a hazardous waste disposal facility. Sometimes you pay a nominal fee and sometimes it's just provided as a free service to try and make sure people don't just dump it into the soil or something.

[DD50]

Yeah I wouldn't. My friend who owns a 99 Ford F-150 ran old fuel in his car once and broke one of the rocker arms. Took him forever to figure out what was wrong with it. I'm not saying that could happen with your car but it is possible.

[93Leg-c]

Thanks guys for all the input! I really do appreciate it!

Steve, what you said about fresh gas eventually cleaning out the varnish is comforting to know.

And, now I'll have to see where and when the city or county will accept the hazmat (fuel) at no charge; I know it's done at intervals so I'll just have to find out when (although I'll be making a lot of trips to finally dispose of all the fuel . . . oh, wait a minute, I'll just ask my friends who have proper fuel containers and I can take it all down in one trip . . . Yay!)

[evolutionmovement]

Yeah, you might have to wait for a free hazmat "turn in" date. It also helps to be friends with a mechanic who regularly gets hazmat picked up (of course, fuel isn't among the usual collected fluids). My city was ridiculous with the off date disposal, wanting to charge me $500 minimum they get per barrel when all I had was a couple 2-liter bottles of antifreeze. They suggested I soak newspaper and let the antifreeze evaporate, then dispose of the papers in the trash. In the winter. Apparently, I should have hung them from clotheslines in my kitchen or something. I left the containers behind when I moved (along with the old front end of the wagon, but I didn't bother to ask for my security deposit).

I'm not 100% positive about it cleaning out the system, but fresh gas is used to clean varnished parts and I've seen long-sitting engines run well again after a tank or so of fresh gas and not have any issues from it, so it looks like 2+2=4 to me.

[Legacy777]

Honestly, if the fuel system remained pressurized, you would not see much evaporation of the lighter hydrocarbons in gasoline. That's a big if, but just something to note. Also, the more full the tank, the better it is to reduce water build up.

I know everyone has said not to use, but you could probably do it. If you were to do it, I'd drain half a tank or so out, and put fresh gas in to mix with the old gas. On all my swaps where my car has sat for a year or more, I've either ran the gas in the Legacy, or I've dumped it out and ran it in the Impreza.

I hate to say this, but when I worked in the liquids side of the oil & gas industry, the phrase "The solution to pollution is dillution" The same holds true for product contamination. You can have a certain amount of diesel in gasoline before it's off spec, same goes with gasoline in diesel, but it's not as much. Keep in mind I'm talking about tanks that hold several thousand to over a hundred thousand barrels of gasoline. (1 barrel = 42 gallons)

If you wanted to be conservative, keep 1/4 of the old tank of gas and put in 3/4 fresh gas along with iso-heet or ethanol and some seafoam.

Also, I know the 90 MY's had drains in the bottom of the tank, not sure if the newer ones did, but something to check. It still sucks draining the gas out since you've got to get the car high enough to get a big enough container under there. I ended up using 5 gallon buckets to collect the gas and then dumped it into a gas container. It would have been a disaster trying to use a funnel and a gas container. I would have had gas all over the garage

[evolutionmovement]

Josh has a point and boats often run on old gas (not diesel, though—if that sits too long, this kelp-like bacteria grows wild in it and hopelessly clogs the tank) without issue. The rule of thumb is to fill it or empty it for storage and stick some water absorber and stabilizer in it. However, that rule of thumb works well with unsophisticated carbureted engines, but I don't think I'd personally trust a turbo MPFI engine with it.

When I was at school in Detroit, during the winter, it came out that gas stations were watering down their fuel tanks, some of them even sticking a garden hose in them at night. A lot of newer cars of the time (mid-late nineties) incurred major engine damage. I got one of those bad tanks with my 1984 GL (1.8, carbureted, distributor, OHV). After twenty minutes or more of cranking (in the friggin' freezing cold winter—good thing that little engine needed almost nothing to kick over) and I was able to limp it a mile or so on what sounded like a single firing cylinder to a name brand gas station that didn't have suspiciously low prices, add some ethanol stabilizer, and fresh gas. A couple miles later, the car ran normal.

[93Leg-c]

Well Josh and Steve, you've given me more things to think about. Thanks!

I've been online trying to find a place to dispose of the gas without charge but nothing seems to be available, at least not right now. Thinking about what you said, Josh, if I cannot find a disposal facility, I may siphon off some of the premium gas in my ss and dilute it in with the fuel in my NA Legacy over a period of time. That way, I can eventually get rid of the gas without ruining anything in the turbo engine. But, if the gas is really bad, well, then I'll come up with a plan B then.

[Subiman91ss]

hey I bought a 91ss about four months ago and it had a full tank after sitting for 14 months... i put in some stabilizer and a bottle of seafoam... drove it nice and had no problems... after the tanks was just under half i filled with premium and another bottle of seafoam(that stuff is amazing) and drove it normal, did great... after that tank was done i replaced my fuel filter and removed my injectors and they looked great, bench tested injectors and strayed fine..

if you are willing to siphon then i would just burn it through your other car as long as its not dark in color or cloudy....
I have burned alot of old gas through n/a cars and had no problems.

luckily the subaru fuel filter takes 2 min to change

[93Leg-c]

bowtieman72, thanks for your thoughts! I appreciate them too!

[Subiman91ss]

hope it all works out for you, without having to drop the tank

[93Leg-c]

Thanks for your well-wish. I'm almost certain I won't have to drop the tank. I'd rather go in from the top of the tank by removing the fuel pump and siphoning out the fuel than drop the tank.

[jp233]

I was going to ask this question also.

My 93 has been sitting for over 3 years now, and I forget how much was in the tank, but I did put some sta-bil in it when it came apart. It has been sitting with the fuel lines "open" (well, I used some screws in the cut hoses to keep down on the smell in the garage). So I was planning on seeing how much was in there, and if it was low (I seem to remember it being low, but I don't really know...) I was going to fill it up with premium and a can of seafoam and just driving it.

If there was a lot of fuel in it.... I'd siphon it out, hopefully the 93's have a drain on the tank that would be nice.

[Subiman91ss]

JP233.... pop open the top of the tank and look in with a flashlight. if its cloudy then siphon, if not then run it.

[kimokalihi]

You really want to look inside for rust too with a light. My car sat for 4+ years and the tank was toast. Completely coated in rust inside and it was half full. I just replaced the tank. What a bitch that was.

[Apex3]

Why risk it for $50 worth of gas?

[kimokalihi]

Why risk it for $50 worth of gas?

No doubt. I filled up the other night for $48! Holy shit. I think its about time I put the tranny in the metro and cut my fuel bill in half.