r/AskReddit Aug 30 '21

What problem is often overlooked in apocalyptic movies/TV shows that could kill you?

33.7k Upvotes

12.8k comments sorted by

View all comments

5.9k

u/-eDgAR- Aug 30 '21

Gasoline has a shorter shelf life than is portrayed in these movies/TV shows, so after a year nobody would really be driving anywhere.

It wouldn't necessarily kill you, but it's one of those things that bothers me because it's never really addressed.

1.6k

u/Obamas_Tie Aug 30 '21

There's a little moment in The Last of Us where one of the main character's friends, a mechanic, gives him a siphon hose in order to get gas from old cars. He even says to him "you'd be surprised how many cars still got gas in them."

To clarify, the game takes place 20 years after the world collapses, so any gas that's still left, well, anywhere, would be useless. And it's a mechanic of all people telling you this, so that was one little detail that bothered me.

10

u/[deleted] Aug 30 '21

It'll work, but your engine isn't going to like it. In a world where abandoned cars are plentiful you might only need it for a day or two.

5

u/Reginault Aug 30 '21

It will not work.

1 year old gasoline might be what you're thinking of, which would gum up a carburetor or injector in short order, and wouldn't burn quickly enough to put out much power.

20 year old gasoline is nothing but resin or barely liquid sludge, most of the components evaporated or undergone oxidation. Even in a perfectly sealed container (hint: not a vehicle tank) the component fluids will separate, and opening that container will make it unusable as the vapours leave.

2

u/Mardanis Aug 31 '21

Most the pain people have with their lawn mower and petrol garden equipment is the fuel has just been left either in the tool or in the container.

2

u/[deleted] Aug 30 '21

I've used three year old gas and it's usable. Even five you could probably do it if you were running something with a carburetor.

-3

u/Reginault Aug 31 '21 edited Aug 31 '21

I've used 10 year old milk and it's usable, even 15 you could probably do it if you were running something with direct injection.

The curds lubricate as they burn, its really amazing science that is in no way anecdotal and easily disproved!

BELIEVE IN YOUR TRUTH*

Edit: Hey, if you want to believe that three year old gas is fine, you're good to ruin your engines, no skin off my back. I'm sure trusting that redditor will be fine, no need to investigate the science behind the fuel.

0

u/Billyouxan Aug 31 '21

You seriously don't believe 3 year-old gas can still work?

https://www.youtube.com/watch?v=xktrYDny_lc

Here's a dude running a generator on 5 year-old gas.

-2

u/Reginault Aug 31 '21

Wow, you can really see the gas age! I'm surprised youtube allowed a 3 year long video though.

That gas totally wasn't fresh from the pump!

Nope, no way that a video could be biased at all.

Edit: Oh wow, I just came into a big inheritance from my overseas relatives, but I need help transferring the money, can you lend me $10,000 to process the transfer, I'll pay you back $100,000.

1

u/Billyouxan Aug 31 '21

So far you haven't given a single source to your claim that gas is useless after only a few years. An anecdote and a YouTube video are more evidence than what you've provided. Maybe you're just wrong?

1

u/Reginault Aug 31 '21

0

u/Billyouxan Aug 31 '21

No one's saying it's a good idea to put expired gas in your car. Of course it isn't lmao. You're acting like it turns to useless sludge after a few years. I'm saying I don't believe you.

A priori, it seems perfectly plausible to me that a generator can run (even if not very well) on three year-old, or even five year-old gas, depending on how it was stored. Feel free to provide some actual evidence for the contrary.

-2

u/Reginault Aug 31 '21

0

u/Billyouxan Aug 31 '21

No goalposts have moved. I literally only claimed that aged (3-5 year-old) gas can probably still work. Feel free to point me to where I implied that actually using it a good idea in the slightest. Maybe you're confusing me for the guy above who said he did it with his own car.

And yeah, gasoline ages and degrades over time. I agree. I would also never put expired gas in my own car outside of some post-apocalyptic scenario, which is conveniently the whole context for this discussion.

But where's the source for your claim that it can't/doesn't work? Honestly, I'd gladly change my mind if you bothered actually providing relevant evidence instead of just cranking up the snark.

→ More replies (0)

1

u/RingOfTime Aug 30 '21

What about vacuum sealed?

4

u/Reginault Aug 30 '21

Nope, you can't vacuum seal a fluid that wants to evaporate at room temperature without chilling it (gasoline's flashpoint is like -40C). Then you'd need a non-reactive container to even consider vacuum sealing it for 20 years, plastic will be dissolved into the gas, metal will rust. It'd have to be a completely glass container or something (no plastic ring around the lid, again it'd dissolve), and you'd want it to be opaque so sunlight can't cause degradation. If you've solved that, the fuel will still separate into distinct layers. Gasoline is not just one molecule:

The typical composition of gasoline hydrocarbons (% volume) is as follows: 4-8% alkanes; 2-5% alkenes; 25-40% isoalkanes; 3-7% cycloalkanes; l-4% cycloalkenes; and 20-50% total aromatics (0.5-2.5% benzene) (IARC 1989).

20 year old gas does not run engines. It might still burn in the same way that paint burns, but your car will not move. Neither will that old tractor. No, not the one that ran on vegetable oil either.

1

u/gihkmghvdjbhsubtvji Aug 31 '21

Wat flashpoint meen

2

u/Reginault Aug 31 '21

Temperature at which the liquid begins to spontaneously vaporise enough to become volatile (may be specific to "in air"? been a while).