What to Do If You Put The Wrong Fuel in Your Car

Accidentally putting the wrong fuel in your car is a common, embarrassing, and costly mistake that can cause breakdowns and inconvenient repairs. Drivers facing this error often dread the consequences, but acting quickly can fix the problem before it worsens. Follow these expert tips and advice to handle fuel mishaps effectively and keep your car safe.

What to Do if You Use the Wrong Type of Fuel

If you notice yikes, the wrong type of fuel has gone into your car, you need to act immediately to prevent significant engine damage. Stop the ignition and do not start driving, then switch off the engine and move to a safe area on the forecourt.

Talk to the fuel attendant and follow the best course of action, which often involves calling assistance from breakdown operators like AA, RAC, or Green Flag, where a specialist division handles misfuel cases through Fuel Assist service.

They can drain, flush, and replenish the tank, clean lines, and ensure further damage is avoided. Always check with your insurance provider to see if charges, including repairs, draining, and cleaning, are covered. From my experience helping drivers in such dilemmas, I’ve seen that immediate calm action and contacting Fuel Assist specialists often saves both the car and wallet, and personally, I once guided a friend through a complete misfuelling recovery which prevented what could have been a major engine breakdown.

Symptoms of Wrong Fuel in Your Vehicle

When a car has been used with the wrong type of fuel, experienced drivers on the road can often tell a tale through early symptoms that are worth spotting before the situation gets worse.

Look for struggles during start or turn of the ignition, excess smoke from the exhaust, unusual engine noise, irregular idle, or lack of power and normal driving speed.

If the car doesn’t stop running smoothly, it’s wise to switch off, pull over, and consider calling a breakdown provider, as these signs can indicate a serious underlying fault likely to cause significant damage. From my personal experience, I’ve driven vehicles after accidental misfuelling and quickly recognized these symptoms, allowing me to prevent full engine failure and guide owners safely to professional help.

What Happens if You Put Petrol in a Diesel Car?

Putting petrol into a diesel car is a common mistake at the pump, where the nozzle doesn’t fit the caps perfectly, but even a small amount can cause serious and severe damage to the engine.

The fuel can circulate through the system, stripping lubricant from diesel engines as the solvent circulates, affecting injectors, fuel lines, filters, and pumps, and the tank may need draining.

The result can be catastrophic, often requiring a completely new engine if left unchecked. From my hands-on experience assisting vehicles with this error, I’ve seen engines suffer minor to major failures depending on how fast action was taken, and personally, I’ve guided drivers to safely drain and flush systems, which prevented total replacement and saved significant costs.

What Happens if You Put Diesel in a Petrol Car?

When you put diesel into a petrol car, it happens most often because the filler nozzles are of different shape, and sometimes the caps fit in a way that makes it difficult but not impossible to accidentally fill the wrong fuel tanks.

The AA has received numerous callouts from unlucky drivers facing this, and even a few litres can start or turn the ignition into a system that suffers serious damage as diesel circulates through GDI engines, affecting injection and other components.

From my personal experience handling such incidents, I’ve seen petrol engines fail quickly when diesel enters, and guiding owners to stop the engine immediately, prevent further circulation, and call for specialist help has consistently avoided major repairs and limited engine harm.

What Happens if You Use E10 by Mistake?

If you accidentally add E10 petrol to a classic car or a vehicle not compatible with modern fuels, the good news is that it is likely to cause only short-term problems and the engine can often run normal without serious damage.

However, repeatedly using the wrong type may affect the long-term integrity of your fuel system, and a guide in comprehensive detail shows how E10 affects certain cars and what potential problems can arise, helping owners avoid future issues.

From my personal experience, I’ve seen a few classic cars take E10 without immediate harm, and by carefully draining and refilling with compatible unleaded, the engine remained safe while teaching owners to always check fuel labels before topping up.

Is Misfuelling Covered on Vehicle Insurance?

Misfuelling your vehicle by adding the wrong type of fuel to a car is a common, accidental problem that can happen to any motorist, but it’s not automatically covered under every insurance policy.

This 2023 Money found that only about one in ten companies and brands of insurers in the UK pay for the event, while other insurers cover the cost of accidental damage if policies contained an exclusion clause exempting the insurer from paying for damage caused by putting the wrong fuel, including cleaning, draining, and refilling the tank.

If it’s not covered, you need to pay for the tank to be drained, cleaned, and repairs done yourself, or alternatively invest in a standalone policy or premium roadside assistance package which includes helping with misfuelling.

It’s always best to read the small print, check for exclusions, and understand your options before paying out of pocket. From my experience advising motorists, knowing which insurers cover misfuelling and acting quickly to call roadside assistance often saves significant costs and stress, and personally, I’ve guided clients to claim or manage cleanup efficiently without further damage.

How to Prevent Misfuelling

To prevent misfuelling in your car, it’s essential to follow a few simple yet effective tips that help avoid what can otherwise be an utter nightmare.

On the forecourt, don’t rely solely on colour or nozzles, which differ between petrol and diesel, particularly when driving overseas or using a new, hire, or family member’s vehicle.

Instead, read the pump carefully before refuelling, consider adding a sticker on the fuel cap to give a gentle reminder, and always select the right nozzle without rush or being stressed, as time pressure is likely to make mistakes that cause accidents.

Stay focused at the pump, avoid distractions, and small, inexpensive devices installed on the filler can assist in preventing accidentally inserting the wrong type of petrol or diesel nozzle. From my experience advising motorists and observing forecourt errors, these proactive steps, including stickers and mindful checking, have consistently reduced misfuelling incidents and saved drivers from costly repairs.

Conclusion

Putting the wrong fuel in your car can lead to costly damage and inconvenient breakdowns, but knowing the right steps to fix the problem quickly saves time and money. Staying focused, following expert advice, and acting immediately protects the engine. Read the comprehensive guide and ensure your car remains safe by preventing misfuelling every time you refuel.

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