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Don’t Rev Your Engine! Why Calling a Pro is Crucial After Putting Petrol in Your Diesel Car

Making a mistake at the gas station, accidentally putting petrol in a diesel car, is a more common occurrence than you might think. While it may seem like a minor error, it can have significant and potentially costly consequences for your vehicle. In such situations, resisting the urge to attempt a DIY fix and calling a professional is the most critical and responsible decision you can make.

Understanding the Risks of Putting Petrol in a Diesel Car:

Diesel engines and petrol engines operate on fundamentally different principles. Petrol ignites with a spark plug, while diesel fuel ignites under high pressure. To put petrol in diesel car disrupts this critical process, leading to several potential problems:

  • Lubrication Issues: Diesel fuel acts as a lubricant for the fuel pump and injectors in a diesel engine. Petrol lacks these lubricating properties, causing increased friction and premature wear and tear on these vital components.
  • Combustion Problems: Petrol ignites at a lower temperature than diesel. This can lead to premature ignition (knocking) within the engine, causing damage to pistons, cylinder walls, and other internal parts.
  • Filter Clogging: The petrol can clog the fuel filter, hindering fuel flow and potentially leading to engine stalling or complete failure.
  • Corrosion: Petrol can damage the fuel lines and other components within the fuel system, resulting in costly repairs.

The Dangers of Attempting a DIY Fix:

While the internet may offer various “solutions” for putting petrol in a diesel car, attempting a DIY fix can be extremely dangerous and exacerbate the problem:

  • Incomplete Removal of Petrol: Even a small amount of petrol remaining in the fuel system can cause significant damage when the engine starts.
  • Improper Handling of Fuel: Petrol is highly flammable and can ignite easily. Attempting to siphon or drain fuel yourself poses a serious fire risk.
  • Further Engine Damage: Starting the engine even briefly with petrol in the system can cause significant internal damage, potentially leading to engine failure and requiring expensive repairs.

Why Calling a Professional is the Best Course of Action:

Calling a professional breakdown service or a qualified mechanic specializing in diesel engines is the safest and most effective solution after putting petrol in a diesel car. Here’s why:

  • Expert Assessment: Professionals can accurately diagnose the extent of the problem and determine the necessary course of action.
  • Safe Fuel Draining: They possess the expertise and equipment to safely drain the contaminated fuel from the tank, lines, and filters, minimizing the risk of further damage.
  • Proper Cleaning: They will thoroughly clean the fuel system to remove any residual petrol, ensuring the engine operates correctly with fresh diesel fuel.
  • Preventative Measures: They may recommend additional measures like replacing the fuel filter or checking for potential damage caused by the incident.

What to Expect When You Call a Professional:

When you contact a professional after putting petrol in a diesel car, here’s a general overview of the process:

  • Explain the situation: Inform the service provider that you accidentally put petrol in your diesel car and haven’t started the engine.
  • Provide vehicle details: Share the make, model, and year of your car to ensure they send technicians equipped for your specific vehicle.
  • Await assistance: A qualified technician will arrive at your location, assess the situation, and safely drain the contaminated fuel and clean the fuel system.

Cost Considerations:

While the cost of calling a professional may seem like an initial deterrent, it’s crucial to remember the potential consequences of attempting a DIY fix. The cost of repairing significant engine damage caused by running the engine with petrol can be far greater than seeking professional help immediately.

Prevention is Key:

To avoid the need for professional assistance altogether, here are some preventive measures:

  • Be mindful at the gas station: Double-check the pump nozzle and fuel type before starting to fill your tank.
  • Use a fuel funnel: Consider using a fuel funnel, especially if you drive different types of vehicles regularly.
  • Invest in a reminder: Keep a visual reminder, such as a sticker near the fuel cap, indicating the correct fuel type for your car.


Accidentally putting petrol in a diesel car can be a stressful experience. However, by resisting the urge to attempt a DIY fix and calling a professional immediately, you can minimize the risk of damage to your vehicle and ensure your safety. Remember, professional help is always the safest and most cost-effective solution in such situations.