Wrong Fuel In Car Symptoms

Symptoms of putting the wrong fuel in a car

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Wrong Fuel In Car Symptoms

There are a few key signs to check for to see if you have put the wrong fuel in your car. Firstly, you need to establish if you have put petrol in a diesel car or diesel in a petrol car as the symptoms for both are slightly different. Bellow shows the main wrong fuel symptoms for both petrol in a diesel car and diesel in a petrol car.


petrol in diesel car wrong fuel symptoms:
• excessive smoking from the exhaust 
• Noisy engine 
• Shuddering of the vehicle 
• Hard to start or will not start 

Diesel in petrol car wrong fuel symptoms:
• Thick excessive smoke from the exhaust
• Engine misfiring
• Engine will not start


Symptoms of putting the wrong fuel in a car
As you can see both will cause excessive smoking where the wrong fuel is unable to burn properly in the combustion chamber. dependant on how much of the wrong fuel is placed into the vehicle, as well as the delivery system used in the vehicle to transfer the fuel from the tank to the engine, some engines will judder to a halt rather quickly and will then refuse to start. If an even mixture of the wrong fuel is in the vehicle or if the vehicle has more of the correct fuel than wrong fuel, you may find the vehicle will run but with most or all the symptoms above, in this case it is important not to run the vehicle in this state as considerable damage may be caused.

Wrong Fuel In Car Symptoms

If you think you have put the wrong fuel in your car but are still unsure the best way to check is to have a look at your receipt for the fuel you last purchased. On the receipt, it will clearly state if you have purchased unleaded or diesel. If you have lost the receipt you can try calling or re-attending the petrol station you attended, most of the time they can check for you and re-print a receipt if you can provide them with a date and the time you filled up as well as the pump you used and the amount you filled up with. 

petrol in diesel wrong fuel symptoms - If that is not possible then the good old fashioned smell test will be your next option if you have a diesel car. Some people can smell petrol a mile off, others can’t easily tell the difference between petrol and diesel just from a single sniff. If you have smelt your filler neck but your still not sure if you have put the wrong fuel in, try to smell a neighbours or family member’s diesel filler neck then immediately after smell yours. If your cars fuel smells different then you have put the wrong fuel in it. You can also collect a small amount of diesel from the fuel station in a clean container and smell that to compare it with. 

diesel in petrol wrong fuel symptoms - If you have put diesel in a petrol car the next best diagnostic would be to disconnect the fuel line at the engine bay. once disconnected place a small rag under the disconnected joint that runs from the tank, turn the key in the ignition to the second position and a small amount of fuel should spray over the rag in the engine. with nitrile gloves get some of the fuel from the rag on the fingers of your glove, rub your fingers together and check to see if it feels oily. If you wait a few minutes with the fuel on the glove it should all completely evaporate, if this does not evaporate and feels oily then diesel is present in your fuel tank. 

What to do once you have checked for wrong fuel symptoms

Once you have established if you have put the wrong fuel in your car you should not start or drive the vehicle any further. If you are driving already you should pull over as soon as possible to prevent any further damage being caused. Once your vehicle is stopped in a safe place call our helpline on 0800 772 3842. If you are still unsure if you have put the wrong fuel in your car after reading this wrong fuel symptoms page and checking the symptoms with your vehicle then please call our helpline on 0800 772 3842 or 0333 772 0842 where one of our wrong fuel experts will be able to help you. 

Please note that the symptoms shown at the top of the page could also be symptoms of other non-related problems. For complete confirmation please complete successfully one of the other methods further down the page.