Old gas sitting in tank for over a year

[tekdeus]

My build took an extremely long time and I am planning to drain and get rid of the 1/3 tank of gas that's been sitting in the tank. I believe the previous owner of my car vented the tank to atmosphere as I could ocassionally smell gas around the engine bay. I am concerned that it may have evaporated a fair bit.

A friend of mine said that this gas could have deposited gum and varnish in the tank and said to add Toluene to flush it out. What's the best thing to do here? I plan to drain the gas out, but should I add something first and shake it around?

 

[IJ.]

Dunno about fuel there but here it's just a matter of dump it out, Slosh another couple of fresh litres around and dump that as well.

 

[tbcmorris]

Old gas equals bad! Do exactly what sir ij said.....I wish I had.

 

[bowsercake]

Old gas equals bad! Do exactly what sir ij said.....I wish I had.

What problems did you have by using old gas?

 

[NashMan]

gas for 1 year no issue at all more then one year like 2 mabey i whould take extra care and flush

but yae drain refiill

if you have rooten tank then new fule filter


done many times no issue

 

[Quin]

What problems did you have by using old gas?

Most cars either wont even start or run like complete shit.

 

[VanSupra]

Brad, old gas smells like varnish and you'll know it's off right away. Dump it if it is. As IJ said dump slosh repeat.. Also spend the $35 for a new filter and replace the older unit while you're in there. Did you find the rear qaurter glass you were looking for?

 

[Poodles]

As gasoline is a mix of many components, some will evaporate faster than others. After a year of sitting and venting it may have vented off all the additives that make it safe for your engine.

This is especially harmful with them using ethanol as the main octane booster now as it's the first thing to evaporate...

 

[IJ.]

Here they add benzine to base stock to raise the octane and it's very volatile and if left sit too long you end up back at low octane.

 

[Poodles]

Yep

Also, a good reason to NOT remove the evap system...

 

[product.sc]

flush! and yes bad gas, if it works, may not be completly safe or good for you engine.

 

[ninja6o4]

I never knew that.. I've always just mixed/filled it with 94 and then drove like a granny for that tank.. on next fillup I knew I had all good gas and was ready to rock!

 

[mirage83]

If the tanks been vented the entire time it's almost a guarantee that rust has set in as well as the gas itself breaking down. According to how bad it is, you might have a fair amount of rust in there, including on the pump bracket and even on the pump depending on who manufactured it. That's how mine was when I bought it. So I would personally recommend draining them dropping the tank to take a serious look at how it looks inside when you replace the filter. A bunch of loose rust particles in the tank can accumulate on the filter after you refill the tank and drive around, meaning you'll have to go through the whole process again... drain, drop, replace filter, etc.

Another concern (as if anyone who owns a supra needs another one) is that the injectors could be gummed up as well. Depending on how bad they are, you might have to spring for a good cleaning.

 

[suprahabsfan]

Mine was sitting for 1 year and 3 months, with 1/4 tank. I took a 5 gallon gas tank and bought 93 octane gas, and made a couple trips to gas station to completely fill up the tank. This diluted the "bad" gas. After the first tank I changed the fuel filter. No problems here. Seeings as this is not the right way to do it, I would reccomend draining tank like IJ said, but I just didnt have the resources to do it at the time. Most likely all that will happen if it was bad gas is your filter will clog and you'll have to change it.

 

[ninja6o4]

I suppose I never had a problem because my old gas wasn't vented.. I just made sure to avoid boost when it came time to drive on that tank again..

 

[IJ.]

Worst case scenario is the Octane drops you detonate the motor and at best pop the HG at worst you break a ring land......

Is saving at most $100 of gas worth that risk?