View Full Version : Old gas

05-29-2013, 02:59 PM
A few weeks ago I tried to pull the fuel pump from the AT because I thought the one in the GT-S was going bad. I got as far as pulling the fuel level sensor when I realized the tank was still full. Needless to say I put a halt on the whole endeavor, which was fortunate because it would've been a whole lot of wasted effort (coil was bad, not the pump).

Now my question is; with gas prices on the rise and wanting to save a few bucks, is it safe to use what's in the AT's tank? It's probably been sitting at full for at least 2-3 years now and I don't know what really happens to fuel after that kind of time.

05-29-2013, 03:11 PM
what color is the fuel? if its that old then it should be black in color and if thats the case the no its safe bc the gas is "bad"

05-29-2013, 03:17 PM
Ehhhh, while it's PROBABLY fine to use it... I drained what was in the supra's tank for 2-3 years when I got it back on the road. A tank of gas is worth not taking the risk, for me.

05-29-2013, 03:23 PM
burn something with it.

05-29-2013, 05:08 PM
From the minute or so that I looked it still seemed pretty clear, I'll check again before I try it though (maybe on the lawnmower first). I just thought I'd get some more "professional" input over my dad's "sure it should be fine, it's gas so it'll still burn" theory. I know usually people storing fuel put some sort of addititve in it to preserve it but I wasn't sure if that was more for the fuel or the container.

05-29-2013, 06:59 PM
It'll run if mixed with fresh gas.

Problem with old gas is all the light components boiled off, will burn fine when mixed with some fresh fuel.

05-29-2013, 09:02 PM
Put some seafoam in there. That'll help take care of the water that has formed in there over the years.

Hipster Lawrence
06-03-2013, 01:32 PM
Nope. Drain it. It's junk. It'll probably be ok in a lawn mower. I work on lots of cars that have been sitting, and have fixed many simply by replacing the gas in the tank.

If the tank is metal I'd drop it and look inside. 2-3 years is a long time. I'd be worried about rust in there.

06-04-2013, 03:49 AM
Old gas was more of an issue when varnish was a significant component -- basically, gasoline is purer and better distilled these days, so it doesn't age in the same manner. More importantly our Celicas use pressurized gas tanks, which keep the lighter components from evaporating out much as a pop/beer can keeps the CO2 in solution, so we don't end up with octane degradation.

The other danger is condensation and water absorption, which actually isn't a problem. Being full your tank would have little air from which water could condense, and even if some did the ethanol in the gas could absorb it. The danger is when there's so much water that it doesn't stay dissolved in the gas and condenses into liquid water, which can cause hydrolock. The fun part of this is that gas can't absorb that much water from air -- the gas' ability to absorb water stops at the same point water would start to condense. With a full tank you avoid the water condensing on the sides of the tank and dripping into the fuel, but again, we have pressurized fuel tanks so the tank isn't constantly sucking in new, moist air from which to condense water.

Motorcycles, outboard motors or lawn equipment with open vents on the fuel system will allow gas to quickly go bad, in as little as a season depending on temperature.

That said, if you have other, less sensitive machinery in which you could use it, might as well. If you're not going to move the AT, you'd still want to fill it and then throw in a fuel stabilizer such as Seafoam.