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5 Simple Reasons to Keep Your Gas Tank Full

Chris Kaiser

Why do today what can be put off until tomorrow? The procrastinator’s dictum sounds dumb when you put it down in digital ink, but when it comes to filling our gas tanks, many of us only do so when it’s absolutely necessary. Turns out, getting stranded on the roadside isn’t the only risk when you’re running on fumes. Below are five reasons why topping off your tank should be added to your list of car maintenance priorities.

Car out of gas

1. Mechanical Issues

Gasoline not only fuels the vehicle, but it also functions as a coolant for the electric fuel pump motor. In modern cars, this pump sits in the middle of the gas tank filled with cool gasoline. A near-empty tank can cause the fuel pump to suck in air and overheat, causing increased wear to the pump.

Each time you neglect pumping gas, gunk from the bottom of the fuel tank could get caught in various components of the vehicle. This sediment in your tank can foul the fuel filter. If the fuel filter doesn’t catch the sediment, you run the risk of clogging a fuel injector. This is less of an issue today with modern heavy-duty plastic fuel tanks, but in older vehicles with metal fuel tanks, rust particulate can be a serious danger.

When a diesel runs dry, the injector pump fills with air and the vehicle won’t start by simply adding more diesel fuel. A tow truck and mechanic may need to get involved to tow the vehicle, remove filters, pressure-blow the fuel lines before adding fuel and priming the engine. Because of this, maintaining a full tank with a diesel engine is even more critical than with a gasoline engine.

The most common concern with allowing your fuel to run low arrives once the mercury dips below freezing. That’s because the condensation that builds up in your fuel tank when it’s low has a greater chance to get sucked into the fuel lines and freeze. Not only can this mean your vehicle won’t start (with frozen water blocking the flow of fuel to the engine) but the lines themselves may become damaged by the expansion and contraction of the freezing water.  

Pumping Gas

2. Gas Mileage

Some will argue that because the gas tank is lighter when its low, a low tank will give the car more fuel efficiency. A lighter load does require less gasoline, but the weight of a full fuel tank is not significant. A gallon of gasoline weighs only 6.3 lbs. (for reference milk weighs 8.6 lbs. per gallon), so even in most large vehicles the total weight of a full tank is under 250 lbs. Your car may actually be less efficient when the tank is near-empty, as more air in the tank can increase fuel evaporation.

3. Safety

car on road on a snowy day

Running out of fuel completely is the biggest danger of allowing your tank to run low, especially during the temperature extremes of winter and summer. Additionally, when an engine dies brakes and power steering can be lost, so running out of fuel at highway speeds can be hazardous in itself. Besides, delaying the expense of a fill-up doesn’t reduce long term expenses, so it is never worth becoming stranded and putting yourself or your family in danger.

Along with keeping the fuel tank full, make sure to have a weather-appropriate vehicle emergency kit in your vehicle. Not all of us are as lucky as Kramer on Seinfeld.

4. Save Time

Some of you might only be allowing your fuel to go flirt with E because you struggle finding time to fill up. But weigh the inconvenience of a five-minute fill-up when you have time after work or on the weekend versus when you have an appointment to get to or a job you’re already late for. Making frequent fill-ups a higher priority avoids last minute emergencies. And all this doesn’t even cover how late you’ll be if you actually run out of fuel.

5. Save Money

pumping gas and saving money

Skimping on fueling up doesn’t save money and could actually lead to expensive repairs and/or a costly tow job. Habitually running the car to empty could lead to fuel pump damage and a repair potentially costing hundreds or even thousands in parts and labor. Filling up can be painful when prices are high, but it is an investment that will protect your vehicle and save you more time and money down the road. 

Trying to save money while driving? The tires are a great place to start. How to save money by maintaining your tires.

Editor’s Note: This post was originally published in February 2015 and has been completely revamped and updated for accuracy and comprehensiveness.

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Chris Kaiser
Chris Kaiser

Chris’ greatest passions include topiary, spelunking, and pushing aging compact cars well past 200,000 miles on cross-country road trips. His taste in cars runs from the classic and esoteric to the deeply practical with an abiding affection for VW Things, old Studebakers, and all things hybrid-crossover.

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  1. Avatar
    Kevin Hyers January 29, 2020

    How far can you run a 2000 volkswagon beetle low on fuel?

    1. Carsforsale.com Team
      Carsforsale.com Team January 29, 2020

      Hey Kevin, it depends how low on fuel exactly!

  2. Avatar
    Lyla Peterson February 27, 2020

    It’s interesting how cars may actually be less efficient when low on fuel due to the potential for evaporation. I just purchased a diesel lawn mower last month, so I need to order some fuel for it before the weather warms up. I will be sure to keep it topped off throughout the summer to maximize efficiency. http://www.fuelmanhawaii.net/services

    1. Carsforsale.com Team
      Carsforsale.com Team February 28, 2020

      Thanks for sharing!

  3. Avatar
    SuperFic June 5, 2020

    It is said that if it is full tank that the fuel consumption is very efficient or fuel consumed somewhat slowly. Is this true or a myth?

    1. Carsforsale.com Team
      Carsforsale.com Team June 5, 2020

      Hi there! As far as we’re concerned, that is a myth!

  4. Avatar
    A Mobile Maintenance September 11, 2020

    Great post, thanks for sharing. Picked up some good and valuable insight

    1. Carsforsale.com Team
      Carsforsale.com Team September 11, 2020

      Thanks for checking it out!

  5. Avatar
    auto electrician auckland September 14, 2020

    This blog happens to be one of the best blog analyzing on 5 simple reasons to keep your gas tank full. It is just a proper critique blog, would suggest others it as well.

    1. Carsforsale.com Team
      Carsforsale.com Team September 14, 2020

      Thank you, we appreciate this so much!

  6. Avatar
    HORATIO September 21, 2020

    Is it ok to fill up my gas tank as soon as the handle pops?

    1. Carsforsale.com Team
      Carsforsale.com Team September 22, 2020

      We like to say, “If the handle pops, you must stop.” There’s a reason it does that. Overfilling can affect the charcoal canister and possibly create longer term issues.

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