The Dangers of Running on Empty: What's Wrong with Driving with Low Fuel Levels?

Running your car on low fuel once or twice isn’t the end of the world because you won’t cause immediate harm - the real risk comes from making it a habit.

Regularly running the tank near empty increases wear on the fuel pump and injectors, often leading to costly, avoidable repairs.

While avoiding refuelling can bring short-term savings, there are some much more effective choices you can make which bring far more long-term benefits – and less chance of an expensive repair bill!

What Happens if You Regularly Run Your Car on Low Fuel?

Regularly driving your car when the fuel level is low can lead to problems with the:

· Fuel pump

· Fuel filter

· Fuel injectors

· Other engine components (caused by additional stress)

 

You can damage the fuel pump

This is the most common consequence of running a car on little to no fuel.

Most modern cars use an in-tank fuel pump which is submerged in petrol or diesel that cools and lubricates it. When the fuel level gets low, the pump is no longer submerged which can lead to overheating, premature wear and, ultimately, a shorter lifespan.

When this part fails, your engine may struggle to receive a consistent fuel supply which can cause combustion problems and may lead to more serious engine damage.

 

You can clog the fuel filter

The fuel filter stops sediment, debris and other sludgy deposits entering the combustion process to ensure your car runs smoothly and cleanly. These deposits build up naturally at the bottom of your fuel tank – so the lower the fuel level, the more likely they are to be sucked in by the fuel pump and clog the system.

This gradually builds over time, so becomes an issue if you regularly run your car on little to no fuel.

 

You can cause problems with your fuel injectors

If you regularly drive your car with low fuel levels, this debris can progress further through the system and affect your fuel injectors as well.

These squirt petrol or diesel into the combustion chamber to provide the energy needed to power your car’s engine. If they try to force sludgy residue into the combustion chamber instead, they can fail and affect your vehicle’s fuel economy.

When this happens, you may also notice poor performance, rough running or misfires, as well as increased exhaust emissions over time. This can contribute to an MOT failure if left unresolved.

 

You can put extra stress on other components

If you regularly run your vehicle with low fuel levels, it’s likely the engine won’t get enough fuel to run reliably (known as ‘fuel starvation’). This is commonly caused by air entering the system or fuel pressure fluctuating – which both happen if the fuel pump is trying to suck up fuel that doesn’t exist.

Inefficient combustion can manifest as hesitation, poor acceleration, misfires or random stalling which, over time, can stress other engine components like the catalytic converter or ignition coils, leading to other expensive repairs.

 

How Much Will it Cost to Fix the Damage of Driving with Low Fuel Levels?

All costs are representative of average price ranges for common UK vehicles and are likely to change based on your make and model, severity of damage and your chosen garage.

We always recommending comparing repair costs at local garages to find the best deal tailored to your exact vehicle.

Here are some of the other components you may damage if you regularly drive your car without much fuel in the tank, as well as some average costs:

While none of these issues are guaranteed to happen if you regularly drive your car with the fuel light on, you increase the chances every time you do so.

That’s why we recommend always refuelling your vehicle once the fuel gauge reaches ¼ of a tank. This keeps the fuel pump consistently cooled, prevents sediment and debris entering the system and avoids relying on the car’s emergency reserve.

Your fuel warning light should be a backup – not a target.

But it also means that your fuel light coming on isn’t the end of the world.

 

How Low Can You Safely Let Your Fuel Tank Go?

Car manufacturers build in a fuel reserve to ensure the fuel pump never runs dry if you’re caught out and can’t fill your car up before the fuel warning light comes on.

But, as with any dashboard warning light, you shouldn’t just ignore it.

That reserve exists to prevent an immediate breakdown, not to support normal driving. If the fuel warning light comes on, you’ll only have about 30-50 miles of range left - enough to find somewhere to refuel; not enough to keep going about your normal day.

Most importantly, you shouldn’t run your car that close to zero regularly.

As a one-off, you can get away with running a bit beyond the fuel warning light coming on. If you do it regularly, you run the risk of causing serious, long-term damage as mentioned above.

That also means it’s safest to fully fill up your tank whenever you refuel. While this may be more expensive than topping up £20 worth of fuel, it also ensures maximum efficiency and longevity.

And there are some really easy ways to fully refuel your tank without worrying about affording it.

 

3 Ways to Fully Refuel Your Car Without Breaking the Bank

Budget for Fuel Costs (based on driving habits)

Have you ever thought about how often your vehicle needs refuelling? Well, if you’re looking to be smart about how much you’re spending on fuel, it’s a question that’s worth asking.

If you know when you’re likely to need fuel, you can work out how much it’s likely to cost each month and budget for it accordingly.

For example, a driver of a small hatchback like a Vauxhall Corsa is likely to need to fill up their tank twice a month, spending around £50 on each refuel. That regular refuelling schedule means they can budget about £125 each month for fuel (£50 + £50 + some buffer to account for fluctuating prices or additional trips increasing their monthly mileage).

Budgeting for fuel means the money is already there when their tank needs filling, avoiding a partial fill or the need to run the tank closer to empty.

 

Where to start: Work out how many times you refuel your car in an average month and the rough cost of a tank of fuel to calculate how much you spend on petrol or diesel each month. This will give you the amount you need to set aside each month to keep your car running.

 

Shop Around to Find the Best Price on Fuel

You might not be getting the best price per litre of fuel by always going to the same petrol station because fuel prices vary depending on the brand you choose.

While you might only save a few pence per litre every time you fill up, this can add up to a saving of a few hundred pounds over the course of the year!

It’s also easy to see who’s charging what each day with a price comparison tool, such as the one available through your free MyGarage account. We update the information daily, showing the cost of petrol and diesel at local fuel stations as well as petrol and diesel availability and any amenities offered.

 

Where to start: Log in or sign up for a MyGarage account to find the best fuel price in your area.

 

Get Rewarded for Being Loyal

Once you’ve found the best price, why not make sure you’re rewarded for choosing them?

Most fuel providers offer some form of points based loyalty scheme, whether that’s Nectar points at Sainsburys and some Esso fuel stations, Clubcard points at Tesco or rewards/discounts via the BPme app.

Plus, loyalty schemes such as Nectar and Clubcard can also help you save on your weekly food shop by offering discounted prices on certain essentials!

 

Where to start: Log in or register for the loyalty scheme that works best for you and make sure you always have the app or physical card handy when you fill up.

 

Is Running on Low Fuel Ever Worth the Risk?

Running your car on low fuel isn’t a safe or cost-effective way to save money in the long-term.

While you may avoid paying for petrol or diesel in the short-term, that can come back to bite as a much more expensive repair bill later down the line.

You’re much better off shopping around to find the best price on fuel and sticking to a regular refuelling schedule, improving your fuel efficiency to make each tank last longer if needed.

That approach is more likely to protect both your engine and your wallet.