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| © Photo: Spencer Platt (Getty) |
We all know that running your car out of fuel is a bad thing for
obvious reasons like the fact that it can leave you stranded. There’s
also a good chance you’ve also heard that running on empty can cause
damage to your car. But what actually happens?
This video by Engineering Explained
dives deep into the topic in full in the following nine-minute video.
And it’s pretty damn fascinating. We’ve talked about this topic before, but sometimes it’s good to have another visual.
Obviously, an engine needs four things to function: oxygen, a spark,
compression, and fuel. Without one of those things, it shuts down, and
you’re not going anywhere. There’s no longer combustion.
The most obvious part of your car that’s affected by running out of
fuel is the fuel pump. Instead of sucking up your gas, it’s suddenly
sucking up a bunch of air. Fuel pumps are designed to be simultaneously
cooled by the fuel as it’s sucked through the pump on its way to the
fuel injectors. Replace the fuel with air, and your pump starts to get
hot. That’s obviously not good.
However, running out of fuel means
that the engine no longer works. So it shuts off. The amount of time
the fuel pump is pulling air and heating up is minimal. But that’s in an
idling scenario. If you’re out there aggressively driving around,
braking hard and making hard turns, the gas in the tank is sloshing
around. In that case, it’s possible that the fuel pump can start sucking
up hot air while there’s still technically still fuel in the tank
because the fuel isn’t necessarily always on the bottom of the tank.
That’s not terrible in and of itself. But if you’re doing that a lot,
then the fuel pump is frequently getting hot and thus wearing out.
Which brings us to the engine itself. What’s the impact on the engine?
The
video notes that impacts on the engine usually rely on some unique
scenarios. Misfires can happen if gas doesn’t make it to all the
engine’s cylinders—but it’s still rare that that could cause damage. If
you’re driving really hard, though, there’s a chance that your engine
isn’t running at the proper air:fuel ratio and therefore is getting hot.
Overall,
it’s pretty rare that just running low on fuel will end up damaging
your car. If you only do it once or twice, you’re not particularly
likely to have any super detrimental effects. Run out of fuel often
though, and you risk doing damage to essential components of your
engine. Anyone who has had to replace a fuel pump can tell you, it’s not
cheap or easy.
It’s always better to be safe than sorry.
