We've all had those autopilot moments - walking into a room and forgetting why you're there, putting the milk in the cupboard, or reaching the petrol station only to realise you've filled up with the wrong fuel in car. While it's a surprisingly common mistake, it's one that can turn from an embarrassing story into an expensive problem if you don't act quickly.
Remember to check what's included in you can be assisted if something like this happens. Some policies include breakdown assistance that will bring you to a nearby garage.
3 steps to follow when you put the wrong fuel in your car
If you realise the mistake while you're still at the petrol station, follow these three simple steps:
The first thing to remember is not to start the engine. If you've already started driving, pull over somewhere safe as soon as possible and switch the engine off. Continuing to drive can circulate the contaminated fuel through the fuel system, increasing the risk of engine damage.
It might feel a little embarrassing, but don't worry, you're almost certainly not the first person to do it, and you definitely won't be the last. Petrol station staff see misfuelling incidents more often than you might think. Let them know what's happened so they're aware your vehicle may need to remain at the pump or be moved to a safe location while you arrange assistance.
Call your breakdown provider, roadside cover provider, or a specialist fuel recovery service. They can assess the situation and arrange a fuel drain to safely remove the contaminated fuel from the fuel tank. Whether you've put petrol in a diesel car or diesel in a petrol vehicle, professional breakdown assistance is usually the quickest and safest solution.
Why Is Using the Correct Fuel So Important?
Modern vehicles are far more sophisticated than many drivers realise. Under the bonnet, the fuel system, fuel pump, injectors, and engine components are all designed around a specific fuel type, and even a small mistake can affect how the vehicle performs.
Diesel and petrol engines operate differently, and the fuel itself plays a vital role in keeping components working as intended. Diesel, for example, helps lubricate parts of the fuel system, while petrol burns differently and lacks those lubricating properties.
That's why discovering wrong fuel in your car isn't simply an inconvenience. The longer the incorrect fuel circulates through the system, the greater the risk of engine damage and costly repairs.
Effects of Putting Diesel in a Petrol Car
Although less common, putting diesel into a petrol car can still cause a range of issues.
As diesel is heavier and less refined than petrol, it doesn't ignite properly in a petrol engine. This can lead to poor performance, rough running, and in some cases, ignition failure.
Common wrong fuel in car symptoms after putting diesel into a petrol vehicle include:
- Difficulty starting the engine
- Excessive smoke from the exhaust
- Engine misfiring
- Rough running
- Reduced power and performance
- Fouled spark plugs
The good news is that if the mistake is identified before the vehicle is driven, a professional fuel drain is often enough to resolve the issue without lasting damage.
Effects of Putting Petrol in a Diesel Car
A wrong fuel in diesel car situation is generally considered more serious.
Diesel fuel provides lubrication for critical components such as the fuel pump and injectors. Petrol removes that lubrication, creating friction and increasing wear inside the system.
If petrol is introduced into a diesel engine and the engine is started, the consequences can include:
- Damage to the fuel pump
- Worn or damaged injectors
- Fuel system contamination
- Damage to fuel lines
- Reduced engine performance
- Costly repairs or component replacement
Modern diesel engines are particularly sensitive to fuel contamination, which is why immediate action is so important.
What Factors Affect Recovery and Repair?
One of the biggest considerations is whether the vehicle has been started. If the incorrect fuel remains in the fuel tank and hasn't circulated through the engine, recovery is generally simpler and less expensive.
Other factors include:
- The type of fuel added
- The amount of incorrect fuel in the tank
- The distance driven after refuelling
- The vehicle's age and fuel system design
- Whether damage has occurred to the fuel pump, injectors, or fuel lines
These factors also influence the overall wrong fuel in car cost. In some cases, a straightforward fuel recovery and fuel drain may solve the problem. In others, damaged components may need to be replaced by qualified mechanics, significantly increasing repair costs.
How to Prevent Misfuelling
Most people who experience a misfuelling incident never thought it would happen to them. The reality is that distractions, busy schedules, and driving unfamiliar vehicles are often the main causes. It's surprisingly easy to grab the wrong nozzle at the petrol station or reach for the wrong fuel pump when you're rushing between errands.
To reduce the risk:
- Double-check the fuel type before filling up
- Read pump labels carefully
- Check the information displayed on the fuel cap
- Pay extra attention when driving a rental or company car
- Avoid distractions while refuelling
What If You Put AdBlue in Your Diesel Fuel Tank?
AdBlue and diesel should never be mixed. AdBlue is designed for a vehicle's emissions system, not its fuel system. If it enters the diesel tank, it can contaminate fuel lines, injectors, and other components, potentially leading to extensive damage.
What If You Put Diesel in Your AdBlue Tank?
While less common, putting diesel into the AdBlue tank can also create problems.
Diesel contamination can damage pumps, sensors, and other emissions-related components. Left unresolved, the issue may trigger warning lights and affect the vehicle's emissions performance.
The best course of action is to have the system professionally inspected and cleaned before continuing to drive the vehicle.
Will 5 Litres of Petrol Damage a Diesel Engine?
This is one of the most common questions drivers ask after a misfuelling mistake.
The answer depends on the vehicle and whether the engine has been started. Older diesel engines were often more tolerant of small amounts of petrol contamination, but modern diesel engines are much more sensitive.
Even 5 litres of petrol can reduce lubrication within the fuel system and increase wear on important components. While it doesn't automatically mean serious damage has occurred, it's always safest to seek professional advice before driving any further.
If you ever find yourself dealing with your car remember the three key steps: don't start the engine, let the petrol station staff know, and contact breakdown assistance as soon as possible.
For extra peace of mind on the road, it's worth reviewing your car insurance and breakdown cover options. Explore cover from OUTsurance and help protect yourself against life's unexpected motoring mishaps.