What happens when you put petrol in a diesel vehicle?

Putting petrol in a diesel vehicle can damage the fuel system and the diesel engine. Therefore, it is important to stop driving as soon as you notice the mistake. When the car starts, the petrol will have already mixed with diesel fuel in the tank and it is then distributed through your vehicle’s fuel system, including the diesel engine fuel pump. This means that some of the damage can be done almost immediately so it is important not to drive the car to far (ideally do not even start the engine). 

Petrol will strip the diesel fuel pump of its lubrication, resulting in parts rubbing together and quickly deteriorating. This produces small metal filings which can clog your fuel system and damage your fuel injectors.

When petrol enters a diesel vehicle, you may notice the following symptoms (while driving):

  • Engine running rough
  • Engine struggling to accelerate
  • Increased smoke from the exhaust
  • Engine struggling to start
  • Knocking or unusual noises from you diesel motor


What to do?

If you accidentally put petrol in a diesel vehicle, it is important to take immediate action to prevent further damage to the engine. Here are the steps you should follow:

  1. Stop the engine: As soon as you realize that you’ve put petrol in a diesel vehicle, turn off the engine and do not attempt to start it. Running the engine with petrol in the diesel fuel system can cause serious damage to the engine.
  2. Do not drive the vehicle: Do not attempt to drive the vehicle, as doing so could cause the petrol to mix with the diesel fuel, potentially causing expensive engine damage.
  3. Call for professional help: Contact a tow truck to have your vehicle taken to a professional mechanic. Explain the situation to the mechanic, who will be able to advise you on the best course of action. It’s important to remember that although towing the car may cost some money, the cost of towing a car is low compared to the cost of potential damage to your engine caused by running the car with the wrong fuel.
  4. Remove the fuel: A mechanic will likely need to drain the fuel tank and flush the fuel system to remove all traces of petrol. Depending on the amount of petrol that was added to the diesel fuel system, the mechanic may also need to replace the fuel filters and clean the injectors.
  5. Repair the engine (if necessary): If the engine has been damaged, the mechanic will need to perform any necessary repairs. This could include replacing the fuel injectors, fuel pump, or other components that may have been damaged by the petrol.

It is important to remember that the cost of fixing a diesel engine after it has been contaminated with petrol can be significant, so it is best to take immediate action to prevent further damage. If you’re unsure about what to do, it’s always best to consult a professional mechanic.

Learn more about what to do >


Petrol out of diesel fuel tank draining and repairs in Hamilton

It is important that petrol is drained from your car’s diesel fuel system before it causes major damage. At Grimmer Motors, we can drain the petrol from your diesel vehicle fuel tank. This will prevent further damage to your car’s fuel system and engine. We also offer repairs for fuel pumps/injectors and engines that have been damaged by petrol in diesel fuel tanks.

For fast, quality and effective fuel draining solutions in Hamilton, contact Grimmer Motors today!


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