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Filled wrong fuel in car on roadside and broken down because of the contaminated fuel

Diesel in petrol car and driven with contaminated fuel
0800 999 1182
07776 120218

Putting diesel in a petrol car is less serious than putting petrol in a diesel car. After starting your engine, the diesel will coat spark plugs and the fuel system, which often leads to misfiring. Your engine may give off smoke, cut out, or fail to start at all. You should drain the fuel system as soon as possible.

What happens when you put diesel in petrol car?

  • A loud knocking sound as you accelerate

  • Excessive smoke from your exhaust

  • Slower than usual acceleration

  • Engine warning light lighting up

  • Engine stopping completely

  • Car struggling to restart

This is because petrol acts like a solvent instead of a lubrication oil to diesel cars. Turning on your ignition sends the fuel between the components and and increases friction, so part os the engine will be damaged.

What to do if I put diesel in petrol car?

  • DO NOT WORRY!! It is essential to have your fuel tank drained along with a full fuel system flush, we also recommend to add in a fuel system additive to help clean the petrol fuel system. After a full system drain/flush has been carried out the risk of your engine/components been damaged is greatly reduced. We have only ever come across a few cases of permanent damage over many years and thousands of cars. Our price start from £110 give us a call and we will have you back on the road in no time!

If you have any other questions, please do not hesitate to contact us.


What to do if you misfuel (put diesel in petrol) your car

If you're lucky enough to realise you’ve put the wrong fuel in your car before starting your engine, do the following:

  1. Leave the engine switched off and don't even put your key in the ignition

  2. Inform the staff at the service station that you've put diesel in petrol car.

  3. You'll be advised to leave your car where it is, or it will be pushed to a safe place

  4. Call us to drain and flush the wrong fuel out of your car. We will be able drain and flush your vehicle's fuel system and get you on your way, unless there's more serious damage.


However, if you realise you've wrong-fuelled after you started up your car, both types of fuel will start circulating, damaging your engine. Here's what to do:

  1. If you’ve already started your engine, turn off the ignition immediately.

  2. If you're already moving, pull over to a safe spot, then switch off.

  3. Again, Call us to drain and flush the wrong fuel out of your car.

How to prevent misfuelling (putting diesel in petrol) your car
  1. Stop and think when you arrive at a service station to refuel and don’t allow yourself to get distracted.

  2. Read the label on the pump and nozzle and double-check the information on the inside of your car’s fuel flap. A circular ‘E10’ or ‘E5’ label denotes petrol, while a square ‘B7’ sign means it's a diesel dispenser. ‘E’ stands for ethanol and ‘B’ for biodiesel.

  3. Check the colour of the fuel nozzle (black for diesel, green for petrol), but don't rely 100% on this colour coding.

  4. If you’re driving a new or unfamiliar vehicle, check and double check the labelling on the inside of the car’s fuel flap.

  5. If you're a diesel car driver, fit an adaptor which replaces the existing filler cap. This prevents you from accidentally putting a petrol nozzle into a diesel filler neck.

  6. If you’re still worried, the best way to avoid misfuelling is to put a sticker on the outside of the fuel flap reminding you which fuel is required.

Wrong fuel: What to do if you put diesel in petrol car

The moment you realize you’ve put the wrong fuel (diesel in petrol car), the ideal situation would be that you haven’t started your car yet.

For a petrol engine, you’ll need to change the fuel filter and clean the spark plugs as well if the car was driven with contaminated fuel.

Call us to drain the fuel tank and flush the entire fuel system.

It's actually a surprisingly common and easy mistake to make. There are approximately 150,000 motorists in the UK who put diesel in a petrol car or the opposite - petrol in a diesel car - and that works out as an average of a fuel-based mistake every three minutes. So, you're definitely not alone in refuelling incorrectly - but you still need to act quickly. If you have put the wrong fuel in your car, it's vitally important that you don't start the engine if possible. Once the car's engine is running, it will start to circulate the newly added diesel around your petrol engine.

The most important thing to do if you have put diesel in petrol car is nothing.


Don't start the engine - hopefully, you will have realised your mistake before attempting to drive off - and make sure the keys are well away from the ignition. Unless you have put only a very small amount of diesel in petrol car, you will need the fuel draining from your vehicle before driving it again.


Diesel in petrol engine

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