For how long after an apocalypse would modern cars remain usable?

Question

Imagine a "soft" kind of apocalypse - nothing like Earth being hit by an asteroid. In particular - 90% of human population have just disappeared (no matter why).

So there are abandoned cities and lots of vehicles, which can be used by survivors. But the question is - for how long?

In some TV shows, even after a few (say, five, ten...) years after the apocalypse, survivors can just pick a random car and use it for transportation. It seems a bit strange to me: I guess tires, batteries or even gas will become unusable.

Answer 1

Tractors, moonshine, rolling starts

Tractors. A tractor would be a good post-apocalyptic vehicle. You should not be madmaxing down the road at 100 mph after the apocalpyse, because stuff might be in the road. Tractors can go over or around stuff, or across fields.

It seems to me like tractors keep their tires a long time. Google turned up this: of course not authoritative but worth something re tractor tires: from http://www.tractorbynet.com/forums/kioti-owning-operating/225700-tractor-tire-longevity.html

Like anything else, it depends on many things. How much you use the tractor, what kind of enviorment (flint rocks, sandy soil, lots of road usage) all add up. but I have seen a lot of old tractors with 30 or year older tires, cracking and splitting and chunks coming off from spinning the tires are a bigger problem than just normal wear. But in general they last a good long time.

from http://kenjonestiresblog.com/blog/how-to-tell-if-it-is-time-for-new-tractor-farm-tires/

For automobiles and other vehicles that travel at fast speeds, a tire failure can be a very dangerous situation.With off road vehicles, such as tractors and construction equipment, while a tire failure can be dangerous- and definitely a big headache- worn times can lead to costly increased fuel consumption and of course the risk of costly downtime.

The main thing with tires is oxidation. If you find a supply and keep them out of the air they will last longer.

Ethanol Thinking about gasoline and diesel. Petroleum fuel has a limited shelf life. Ethanol does not - a bottle of everclear will be fine 100 years from now, and plus you can make your own moonshine. I was very impressed that in Mythbusters a normal 2010 car ran fine on moonshine.

http://mythresults.com/moonshiner-myths

For the performance testing, the team tested three different strengths of moonshine: 151 proof, 170 proof, and 192 proof in a 0 to 60 mph (97 km/h) acceleration test. The car would not start on 151 proof, it averaged 19.4 seconds on 170 proof, and averaged 9.0 seconds on 192 proof (96% ethanol). Next, at Petaluma Speedway, Tory drove 3 laps running gasoline and 3 laps running 192 proof moonshine. The lap times in the moonshine-powered car were marginally better. Tory noted that even though the acceleration was slower on moonshine, the effect gave him better control on the dirt surface of the track.

For the longevity test, they went to Thunderhill Raceway Park. Grant, in a moonshine-fueled car, attempted to outrun Kari and Tori in an identical but gasoline-fueled car. Grant was able to stay ahead of them after 3 laps totaling almost 10 miles (16 km). The team declared the myth confirmed, but Kari commented that standard car engines are not designed to run on ethanol and that it gives poor gas mileage.

Rolling start for dead battery Re battery - how important is a battery anyway? For an automatic transmission you need one to start the car. The battery powers a starter motor whose only job is to get the engine turning fast enough that it can go by itself. But if there is a clutch pedal & your battery is dead you can start the car by rolling it up to speed and then popping the clutch. There is no reason you could not do that over and over. When you are underway if your alternator is good you should be able to run the headlights and listen to your CB.

I am not certain you can do a rolling start with a tractor but I do not know why not - if it is a manual transmission the principle should be the same.

My recs, Omega Man:

• 1: Tractor if you can find one.
• 2: Late model stick shift if no tractor
• 3: Stash some spare tires in airtight environment.
• 4: Stock up on Everclear (good idea anyway). Or Bacardi 151 and mothballs
• 5: Park on hills so you can easily start when your battery dies.

Answer 2

Fuel expires, tyres rot, most importantly: batteries go flat.

Most of my cars of recent years have been inaccessible with a flat battery, even trying the key in the lock gets you nowhere because that apparently just sends a signal to the servo to open the lock. (Information from direct experience)

• Fuel, a few months
• Coolant can last a decade or more
• Tyres last 5-7 years if they keep pressure or shape but if flat they'll degrade fairly quickly on the creases
• Engine oil should be fine for years
• Brake/Clutch/Power steering fluids should be fine assuming no leaks and it's actually brake fluid not water which degrades the seals
• Screen wash not worth checking, the nozzles will have been clogged by dust
• The battery will last depending on condition and load, anything from a few weeks to a few months. Once it's been flat it's effectively useless, so there's no point shopping around the town for a good battery after that first year, they'll all be dead.

I'm assuming you don't much care about condition of bodywork or emissions standards. Cars in dry places will last longer, cars near the coast affected by saltwater will probably be gone by the time you find them.

Target vehicle: Any 1980s diesel.

Why? These things blow smoke like a Russian aircraft carrier but once running they ignite on compression so it doesn't matter if there are no electrics at all. Also they're rough old engines and will run on used chip fat if you sieve out the crunchy bits. Some of the old mercs were famous for running on vegetable oil the only downside was the car smelling like a chippy.

Also security: Most of the cars of this period had keys you could buy off the shelf, entire model ranges (Vauxhall Cavalier) were famous for effectively using the same key. Here's a video of Jeremy Clarkson showing how to start a car of the period without even bothering with the key

Answer 3

Older is better

Modern cars are far more complex than older engines. 1970s and 1980s era cars were designed with lots of extra space, fewer parts, and were easier to work on. I can remember my father performing maintenance on cars in the 1980s, using parts off even older cars left out in junk yards for years with no maintenance. It took skills, patience, and time. But it was possible.

Modern cars, even "trivial repairs" like replacing an alternator or a belt can require specialized tools and multiple people. I had a 1990s car with an alternator that went out. To replace the alternator, the mechanic had to remove the bolts that hold the engine to the frame and actually move the engine with a larger lever ("rocker bar"). It was not a trivial repair after all.

Computers inside cars will start to fail as the sensors wear out. They have more "fidly bits" that require higher tolerances to even work. Electric motors to drive cooling fans rather than belt-driven fans powered directly by the motor. Electronic fuel injection. Automatic transmissions with sensor arrays.

Fuel fails first. Modern gasoline has ethanol (alcohol) in it. When that and other volatile chemicals evaporate, the fuel forms a kind of "varnish" that coats everything. When you buy a new lawn mower, the gas tank is often white. After 2-3 years of use, that gas tank is a redish brown. You can use treatments that help slow this process. But by the end of your first year, most gasoline in the US at least will be useless. Ethanol-mix fuels have a shelf life of about 100 days. More here. If you can find ethanol-free fuels, they last longer, but its hard to find.

Stick to diesel. The fuel itself is still volatile and shouldn't be stored for more than a year, but these engines can be converted to vegetable oil or similar replacement fuels. Those fuels will wear engines out faster, but can be created by your post-apocalypse world, whereas gasoline is probably not possible.

Plastic/electrical parts fail next. Tires. Belts. Wires. Batteries. These will go next. Plastic/rubber compounds will dry rot. Batteries will fail. Modern cars require batteries. You can't run a car without one. Older cars can at least be coaxed to start without a solid, good, battery.

Roads eventually fail, too. You're going to need off-road vehicles. At first, because so many cars are clogging roads that they're useless. Or get a bulldozer -- with that fuel efficiency? But later, the roads and bridges will fail. After a few seasons of freezing and thawing, potholes will take over. Grass and then trees will grow into the cracks and holes.

Have you considered horses? Long-term, horses make more sense than cars. Sure, use cars while you can, for as much as you can. But plan on their expiration sooner than you would like. Work cars as hard as possible in the first few months. But after that, start working to phase them out. Horses can be bred for work or for speed, they can be trained, and they eat grass. Much easier to produce grass than fuel and rubber tires and spare parts and....

Answer 4

Quite awhile. There will a Mechanic's Guild.

Your world will have an economy of people good at keeping cars running. They will have many eager apprentices. Many others will scoff and prefer their horses, which are easier to refuel.

The craftsmen will have ways to address the various problems. They will know which cars to preserve (figure cars made by the millions, toyotas, F150 and 1500/2500 trucks).

They will know to gather and store fuel, cleanse contaminated or old fuel, or make new fuel. They will jealously guard a trove of collected tires in cool dry places.

Keeping batteries topped up is easy with solar panels, but that only works until the batteries get too old. Lead-acid batteries are ancient technology, and the materials are very recyclable, so it's likely they'll find a way to make them.

So the answer is "indefinitely, but only for a few people." The issue will be a lot more about who has the influence/wealth/control to be one of the ones with cars. Roads will be a bigger problem, because with so few users, no one will want to maintain them.

Your heroes will have little chance of randomly scavenging working vehicles, because the guild will have been there first, picking anything usable.

Don't forget the Robber Barons

Almost half of America's rail miles were removed in the 20th century, mostly in the northeast. What remains is maintained in absolutely pristine condition, with technologies that didn't exist in the "golden age." It will last for many years with minimal maintenance (assuming train weight and speed fall significantly, as they would without big industry and electric signaling).

Rail equipment is made of tougher stuff. So passenger rail would be the dominant mode of inter-town transport. There are plenty of passenger trains available when you figure the urban commuter trains.

Of course, this monopoly will make them formidably powerful, especially since they have their own genuine police departments, who will step up to quell lawlessness where it affects railroad interests. They will collect Hummers and MRAPs from municipal police departments who "aren't using them anymore". And they will mobilize scary-fast because they will travel the long distances by rail. This will make them a force only fools will challenge. Effectively the railroads will either make the government they need, or prop up a national government as needed.

They won't be against private vehicle usage. If anything they will help support it, because their own needs for small vehicles and engines will help sustain the mechanic's guild. On the other hand they will compete in the market for working vehicles and for mechanic's time, i.e. Good luck getting a car fixed in Omaha if it doesn't say Union Pacific on the door.

Answer 5

Gasoline has a shelf life of about three months.

You could make your own fuel, probably some ethanol mix, but then you will have to deal with cars breaking, with good care and regular maintenance I would say you can keep your car in good, working order for about 11 years (personal experience)

Answer 6

This is not a wholly theoretical question. Cuba has not imported cars or car parts for more than 50 years, but the the island's cars have been kept running through a combination of cannibalization, improvisation, and sheer will.

(Incidentally, the paucity of imports is usually blamed on a boycott of its large neighbor, the US, but this is not the case. American-made cars are not the majority of cars on American roads. Nothing stops Cubans from buying Toyotas, Hyundais, or Tatas except what stops me from buying Maseratis, lack of the money to do so.)

Probably, the best bet would be to start with Diesel-powered vehicles. The high-compression engines are much less sensitive to fuel-types, and can be adjusted to burn almost any burnable liquids. Gasoline-powered engines are far more sensitive and have many more parts to keep working.

Someone mentioned ethanol. Pure ethanol attacks the plastics and resins used to make parts of the fuel pathway, and is much lower energy, both by volume and by the labor expended refining it than petroleum-based fuels. If your survivors are in California or Texas, an early priority would be to get the oil wells and oil refineries working again.

Answer 7

Older (non common-rail) diesel vehicles are a good bet, diesel fuel can remain viable for a year or more if it's stored somewhere clean and dry and older engines can be persuaded to run acceptably relatively degraded diesel (unlike modern ones which are much more sensitive to fuel quality) or even on used cooking oil which will help extend your supplies.

Flat batteries are a problem in terms of "jump in and go" as they will go flat in a month or so (less if the car has a persistent drain such as an alarm system) but assuming your apocalypse hasn't obscured the sun you could use a solar charger to get one going. It'll take a while though so if there is peril that would prevent you staying in one place for a couple of days you are going to struggle. Once you've got one charged however it's just a case of using it frequently enough to let the alternator do it's job. Once you've got a running motor if you can gather a few spare batteries you can use the working car's alternator to charge these up giving you the ability to jump start other vehicles, hell if you can get your hands on a solar generator (one off this list would be a start: http://www.jpost.com/PromoContent/8-Best-Reviewed-Portable-Solar-Power-Generators-for-2016-439477) then you could use regular mains-powered car battery chargers or even charge plug-in electric vehicles!

Answer 8

Older is definitely better, but there are other things you need to know about in the first few months after the disaster.

Firstly, lead-acid batteries self-discharge over a few months and once discharged, they sulphate and become scrap. So as soon as possible, you need to scavenge lots and lots of batteries and put them on float charging. How? Well, a solar panel generates ~250W at ~30V on a sunny day and ~25W on a cloudy one. If one knows a little electronics, a low-current precisely regulated voltage source is not hard to lash up. Or you could recharge them every month at higher current, using a scavenged DMM (digital multimeter) to work out when they are fully recharged. Or hack the mains-driven float charger in a battery distributor to work off solar panel DC instead.

Next, Tyres and other rubber components will rot in air. Much faster, if in the sun, and in the case of tyres if they go flat with the weight of a car on them. So you'd want to stockpile appropriate hoses and tyres, and store them under cover. A cave or a deep basement would be ideal (stable cool temperatures year-round).

Finally, fuel. It will probably last a year (for use in a vehicle without modern fuel injection) but it won't last a lifetime. Modern fuel-injected vehicles, most especially diesels, are highly sensitive to the quality of your fuel. Degraded fuel will destroy the injection system.

So to the choice of vehicle. I'd suggest two options. Firstly, light military vehicles (jeeps, land-rovers, humvees). Preferably, older. The military want their vehicles to run on whatever is available: dodgy diesel, kerosene, petrol, cooking oil, heating oil, and to heck with the clouds of smoke. If anything will run on decades-old fuel, an elderly mil-spec vehicle will.

Secondly, if you can find one: a car or bus that has been converted to run on LPG (Liquid Petroleum Gas). I expect that a tank of LPG (mix of propane and butane) will stay much the same until the tank fails and it vaporises. Centuries, probably. Such cars are rarities, but they do exist. The other snag is that LPG cannot be used for compression ignition. Such a car will depend on spark ignition, and therefore on having a battery.

Fork-lift trucks commonly run on LPG. Might it be feasible to hybridize a forklift truck and a petrol car using just hand tools and welding gear? Those prongs out the front might actually be useful for shifting debris off the roads.

If all the lead-acid batteries are scrap by the time you get on top of things, there may be alternatives. An AA NiMH rechargeable battery is not destroyed by going flat and is typically 2Ah. Eleven in series is ~13.2V. About sixty in parallel should be able to power a starter motor (briefly needs several hundred amps under effective short-circuit conditions). So you need to connect up an array of ~660 AA cells to replace a lead-acid battery. Maybe. I've never tried! The voltage is not exactly the same as a lead-acid battery, so the vehicle couldn't be trusted to charge them correctly without some electronic tweaking. But it would start and run minus the alternator, with a solar panel lash-up for charging the battery pack.

Or you might be able to find a NiFe battery. These are the ultimate rechargeable batteries for post-apocalyptic survivors. Overcharge them, undercharge them, short-circuit them, leave them to go flat and then years longer: they will survive it all. Because they weigh twice as much as Lead-Acid and because they go flat all by themselves in a mere few weeks, they are now rarities. The London Underground (railway) still uses them to power its overnight maintenance train locomotives, and if there are any pre-war lifts (elevators) still in use in their original form, they were used for regenerative start/stop operation.

Summary. Batteries, petrol/diesel fuel, rubber components: these are the things that you can't rely on scavenging, because they decompose quite rapidly whether in use or not. For the rest, if you can build a fleet of identical vehicles, then every part that breaks can be replaced from one of the others, for many decades. (The ultimate longevity of electronics is probably not yet known, which is another reason why old vehicles pre-dating mission-critical automotive electronics are best).

Answer 9

Your main problems won't be with vehicles. Cars can run on wood-gas with unsophisticated modifications, so fuel's not the biggest problem. Batteries can be recharged and reconditioned and basic ones aren't that difficult to make. Spare parts can be sourced from the millions of abandoned vehicles all around you. A lot of those vehicles will be relatively protected from the elements, and lets not forget the thousands of junk yards we've got with spare parts already stripped and sorted for you.

Your biggest problem will be the infrastructure, the roads basically.

Keeping cars running should be within the capability of most small communities, that gear head who used to bore you at parties ? He's pretty damn essential now. Now hands up everyone who knows someone who can fix a road, or a bridge, how about a tunnel ? Even if you did know someone the resources they'd need would make road building and repair out of reach for all but the largest and most developed of communities.

99% of modern cars will be usable only until the potholes get too deep, a couple of winters basically. You can go for specialist vehicles, off road, amphibious even, but the less mainstream the vehicle then the harder it'll be to maintain them. Personally I'd opt for a truck that can run along railway tracks as well the road. Railways and bridges won't have as much wear and tear, they'll last longer, they won't be blocked by 1000s of abandoned vehicles, most rail tunnels will be passable. You can switch between road and rail as needed.

Answer 10

Batteries used to be sold without sulfuric acid. The customer (or service store) would add that. A battery without acid will be good forever. Chances are that after a couple of years, no car on the street will have a battery with a charge though.

So, no, you're not going to walk up to a car in a parking lot 5 years after and drive away. Diesel is the way to go. As far as gasoline engines go, if the engine of a new car is kept "dry" then old gasoline can be used (possibly needing filtration first). It doesn't go "bad" in the sense that it doesn't burn, but the ignition won't be as efficient without the additives, which may have plated out (as many others have mentioned).

Tires do become more and more brittle. Modern cars use the air in the inner tube to reduce the transmission of shocks from the road to the driver (and passengers and cargo and engine). There's no real reason you couldn't use steel wheels, if you'd be willing to tolerate the jolts.

Sure you could store tires somewhere where there's no air (oxygen), and where it's cool. But that doesn't seem very practical to me. Chances are after 10 years or so, you'll have to have found a replacement for rubber tires. If you limit speeds to horse and buggy, then you might be able to fill the tires with saw-dust, rags, or pretty much anything and have them work for a while, even after decades.

The real question is the electronics. My guess is that they'll be good for decades, but its a real unknown. The other problem is plants, insects, and small animals. They're going to live in any available car, in the nooks and crannies. Again, I doubt that a car on the street will be likely to start after 10 years. Cars in dealerships and in garages are much better choices.

Answer 11

I'm going to go for an answer no-one has explored here yet.

I have a fully electric car, solar panels, and an off-grid inverter.

Solar panels have a warranty of up to 20 years, the inverter about the same, these could easily go out to 30 or 40 with luck and maintenance. I think the EV will, on low mileage and reasonable care, last 20 years at least, it's an unknown, but there are very early model EVs on the road from 2009 that are still going strong, and technology has improved a lot since then.

The car has very few moving parts and the maintenance schedule is basically non-existent (no filters, the oil is self-contained and never gets 'burned', the brake system is sealed, etc.) The wheels are a standard size, and if it's just used to get around at low speeds, I could get away with one or two changes in all that time.

Now in terms of 'jumping in and it just working', I think a full charged EV now, would still be driveable within the first year or so (if you can get hold of the keys); the battery would hold a small amount of charge through that time, it wouldn't be great, but it wouldn't be dead.

If I could get my hands on a diesel powered generator, I'd have the best of both worlds, I could put whatever will burn in the generator, use it to charge my car with less risk of gumming it up with homebrew concoctions!

Answer 12

Those mentioning focusing on older diesel engines because they can run on other fuels - it's worth noting that, in a real pinch, diesels will run on engine oil itself. As explained on Diesel Engine Runaway, motor oil has roughly the same energy density as diesel fuel. It's likely more viscous than diesel so would give the fuel pump more work to do, but consider that large automotive stores will have shelves full of oil in airtight bottles. A supply like this could last years, probably enough to get you from one side of whatever country to the other. Okay, the emissions would be terrible, but in an apocalyptic scenario, that's pretty low priority, and with so few cars in use, the planet might even tolerate it.