What to Do If You Accidentally Put Petrol in a Diesel Car

Accidentally putting petrol in a diesel car happens more often than you might think and can lead to costly repairs if not handled carefully. Here’s a guide to understanding what happens when petrol meets a diesel engine, and what steps to take if you make this common mistake.

What Happens When Petrol Enters a Diesel Engine?

Diesel engines are designed with very different components than petrol engines, and using the wrong fuel can cause severe damage. Diesel fuel has natural lubricating properties that petrol lacks. Without this lubrication, the diesel fuel pump, which operates at high pressures, can easily fail. When this happens, metal fragments from the pump can clog the fuel lines, filter, and injectors. If the petrol reaches the engine, it can cause even worse issues, including potential melting of engine parts due to the added heat and stress.

In severe cases, the engine may experience uncontrolled fuel detonation, leading to melted pistons or an engine failure that might require a total rebuild.

Steps to Take If You’ve Put Petrol in a Diesel Car

1. Do Not Start the EngineThe best-case scenario is catching the mistake before you start the engine. If you realize what’s happened while refueling, stop pumping immediately and avoid starting the car. Notify the petrol station staff so they’re aware of the situation and understand why you won’t be moving your vehicle.
2. Call for Roadside Assistance or a SpecialistRoadside assistance services or companies specializing in wrong-fuel recovery can help. They’ll usually tow the vehicle to a specialist or may conduct on-site repairs if the engine hasn’t been started. Typically, they’ll drain the fuel from the tank, replace the fuel filters, prime the lines, and ensure the car is safe to drive with fresh diesel.
3. If You’ve Started the EngineUnfortunately, if you’ve already started the engine, the potential damage could be significant. In this case, the vehicle should be towed directly to a diesel specialist for a thorough inspection and repair assessment.

What Does It Cost to Fix a Petrol-Diesel Mix-Up?

The cost of repair depends on the situation:

• If the Engine Wasn’t Started: Expect to pay around $200 to $500 for fuel drainage, filter replacement, and labor.
• If the Engine Was Started: Repairs can range from replacing the fuel pump and filter to more extensive work, which might run around $1000. In severe cases where the engine has suffered internal damage, the bill could reach $6000 to $10,000.

These figures don’t include the cost of refueling with the correct diesel fuel, so the total can add up quickly.

Does Insurance Cover Misfuelling?

Most insurance policies do not cover damages caused by putting the wrong fuel in your car, and warranties are typically voided as well. While some sources say certain policies “may” cover misfuelling, it’s rare to find an Australian insurance provider that does.

Final Takeaway

While putting petrol in a diesel car can be costly, following these steps can help minimize the damage and expense. Double-checking at the pump before refueling is always the safest way to avoid this headache altogether!