What Happens When You Put Petrol in a Diesel Car and Diesel in a Petrol Car?
Filling your vehicle with the wrong type of fuel can be a stressful and costly mistake. It’s easier to do than many people think, especially if you’re in a rush or driving a rental car with unfamiliar requirements. Here’s a breakdown of what happens when you put petrol into a diesel car and diesel into a petrol car, along with tips on what to do if it happens.
Petrol in a Diesel Car: A Costly Mistake
What Happens?
Diesel engines rely on the fuel acting as both a lubricant and a combustion source. When petrol is introduced, it disrupts this process, leading to severe mechanical issues. Here’s why:
- Loss of Lubrication: Diesel fuel lubricates the engine’s components, such as the fuel pump. Petrol, being a thinner fuel, lacks this lubricating property and can cause the fuel pump and other components to grind together, leading to significant damage.
- Pre-Ignition Issues: Diesel engines ignite fuel through compression. Petrol, being more volatile, can ignite prematurely under compression, causing knocking noises and potentially damaging the engine.
- Clogged Fuel System: Petrol can damage seals, injectors, and the fuel filter because diesel engines are not designed to handle petrol’s chemical composition.
Symptoms of Petrol in a Diesel Car - How To Know
Not sure if you may have added Diesel to your petrol car? These are some indicators you might have done that:
- Difficulty starting the engine or failure to start.
- Increased engine noise (knocking or pinging sounds).
- Excessive smoke from the exhaust.
- Reduced power or stalling while driving.
Potential Damage After Putting Diesel In A Petrol Car
The extent of the damage depends on how much petrol was added and whether the engine was started:
- Small amounts of petrol: Minimal damage if identified and drained promptly.
- Engine started: Severe damage to the fuel pump, injectors, and even the engine itself.
Diesel in a Petrol Car: A Different Kind of Problem
What Happens?
Petrol engines are designed for a high-combustion fuel like petrol, which ignites with the help of a spark plug. Diesel, on the other hand, is a heavier fuel that doesn’t vaporize as easily. When diesel is introduced into a petrol system, it can wreak havoc in the following ways:
- Fuel Delivery Issues: Diesel is too thick for petrol injectors and can clog the fuel system, preventing proper fuel flow.
- Incomplete Combustion: Diesel doesn’t ignite well in a petrol engine, leading to unburned fuel in the system.
- Engine Damage: The presence of unburned diesel can coat spark plugs and damage the catalytic converter, a critical (and expensive) component in modern petrol cars.
Symptoms of Diesel in a Petrol Car - How To Know
- The engine misfires or fails to start.
- Thick, black smoke from the exhaust.
- Noticeable lack of power while driving.
- Unusual knocking noises.
Potential Damage
- Fuel system contamination: Diesel must be drained to avoid long-term damage.
- Catalytic converter failure: Diesel residue can damage this essential component, leading to costly repairs.
What to Do If You Use the Wrong Fuel
- Don’t Start the Engine!
- The most critical step is to avoid starting the car. Starting the engine circulates the contaminated fuel, increasing the likelihood of damage.
- Call for Help:
- Contact a roadside assistance service immediately. Many providers offer fuel drainage services to remove the wrong fuel safely.
- Drain and Flush the System:
- The fuel tank and fuel lines will need to be drained and flushed to remove all traces of the incorrect fuel. In some cases, the fuel filter may also need replacement.
- Inspect for Damage:
- Have a mechanic inspect the fuel pump, injectors, and other components to ensure there’s no lasting damage.
How to Avoid Misfuelling
- Double-check the pump: Always verify the fuel type before selecting the nozzle.
- Use reminders: Attach a label or tag near the fuel cap indicating the correct fuel type.
- Take your time: Avoid rushing during refuelling, which is when mistakes are most likely to happen.
- For rentals or new cars: Confirm the fuel type before driving away.
Who Can I Call If I Put The Wrong Fuel Type In My Car?
If you have added petrol to your diesel vehicle or diesel to you petrol vehicle. Call the experts at Bennett Motors to handle draining, flushing your vehicle to ensure there is no long term damage to the vehicle. Contact us today to schedule an appointment or visit our workshop to experience professional care for your diesel vehicle by qualified diesel mechanics!