*First Things First: Don’t Start the Engine!*
It happens more often than you’d think: one quick slip-up at the pump, and you’ve put petrol in your diesel car, or vice versa. Misfuelling is an easy mistake but can have serious consequences if not addressed quickly. Here’s a straightforward guide on what to do if you’ve put the wrong fuel in your car, including tips on preventing damage and getting back on the road safely.
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What To Do If You’ve Put The Wrong Fuel In Your Car
If you realise you’ve put the wrong fuel in your car before starting the engine, you’re in a good position to avoid major damage. The real trouble begins when the wrong fuel circulates through your engine. Here’s what you should do immediately:
- Leave the engine off and don’t turn on the ignition.
- Put the car in neutral to keep it stationary.
- Alert the petrol station staff about the situation.
- Call for assistance to drain the fuel tank and flush the system.
If you are currently reading this article while your car is in this situation, try contacting us or seeing our wrong fuel rescue service.
What to Do if You’ve Already Started the Car with The Wrong Fuel
If you’ve already started the engine, it’s critical to turn it off as soon ASAP. Here’s what to do next:
- Turn off the engine as soon as it’s safe to do so, ideally in a secure location.
- Avoid driving further as this can increase the damage to your engine.
- Call a breakdown service for a drain and flush service to remove the wrong fuel.
With quick action, you may prevent extensive damage, though you may still need some repairs to restore full performance.
Petrol in a Diesel Car: What You Need to Know
Putting petrol in a diesel engine is the most serious type of misfuelling, as diesel engines rely on diesel fuel to lubricate the fuel pump and injectors. Petrol acts as a solvent, causing friction and wear that can lead to costly repairs. Signs of petrol in a diesel car include:
- Knocking sounds while accelerating
- Excessive smoke from the exhaust
- Slower acceleration
- Engine warning light illuminating
If left unchecked, this type of misfuelling can damage the fuel pump, injectors, and other critical engine components.
Diesel in a Petrol Car: Less Severe but Still Important
Diesel in a petrol car is generally less damaging than petrol in a diesel vehicle, but it can still cause performance issues if the engine is running. Signs of diesel in a petrol engine include:
- Engine misfires
- Excessive exhaust smoke
- Stalling or difficulty restarting
The solution here is the same: contact a professional to drain and flush the fuel system before attempting to drive further. Doing this quickly can often prevent serious damage to the engine.
Why Quick Action Matters
Leaving the wrong fuel in your car—even overnight—can lead to a larger repair cost, especially in diesel engines. Immediate action reduces the chance of the wrong fuel circulating through the engine and causing irreparable damage.
Common Symptoms of Wrong Fuel in Your Car
If you’re not sure whether you’ve used the wrong fuel, watch out for these symptoms:
- Engine misfires or stalls suddenly
- Knocking noises or strange sounds from the engine
- Reduced performance or slower acceleration
- Excessive smoke from the exhaust
- Engine warning lights on the dashboard
At the first sign of these symptoms, pull over safely and turn off the engine. Contact professionals who can help you when you put the wrong fuel into your car.
Misfuelling Prevention Tips
Misfuelling is surprisingly common but avoidable with a few simple precautions:
- Double-check the pump before you fill up—don’t rely on the colour of the nozzle alone.
- Stay focused while refuelling, and avoid distractions like your phone.
- Consider adding a fuel cap reminder to ensure you’re using the correct fuel every time.
- Take your time at the pump. Rushing increases the chance of a mistake.
I have a Rental Car, what fuel does my car take?
Most rental cars have a sticker on the fuel flap indicating whether it is diesel or petrol. If it doesn’t, you should try contacting your rental car provider. Otherwise, inside the fuel flap you may see different codes for fuel types. Some of the common ones:
- Diesel: B7, B10
- Petrol: E10, E5, E85
FAQs on Misfuelling
How much wrong fuel is too much?
Even a small amount of incorrect fuel can lead to issues, so it’s best to take action regardless of the amount.
Will my insurance cover misfuelling?
Some insurance policies include misfuelling assistance, but it’s best to confirm with your provider.
How long does it take to drain the wrong fuel?
A typical drain and flush can take around 30-60 minutes, depending on the vehicle type and extent of contamination.
