Quick answer: don’t start the engine or turn the ignition on. Tell the servo staff, make the car safe, and call a mobile fuel drain service. If the engine hasn’t run, a drain and flush almost always prevents any damage.
What to do, step by step
- 1Don’t start the engineNot even to move the car or check the radio. Turning the ignition on can prime the fuel pump and pull the wrong fuel into the system.
- 2Stop filling and tell the console operatorThey can stop the pump, help you push the car clear, and note the incident.
- 3Make the car safeHazard lights on, gear in neutral (or park), handbrake on once it’s in a safe spot. Push it with help, never by starting it.
- 4Note what went inCheck the pump display for the fuel type and litres. Note whether the engine was started, even briefly.
- 5Call a mobile fuel drain serviceMost cars are drained, flushed and refuelled where they are in 30 to 60 minutes, with no tow needed.
- 6Keep your receiptIt shows the time, pump and amount, which helps the technician and any insurance or rental claim.
If you’ve already driven the car
Pull over as soon as it’s safe and switch the engine off. Common signs are a rough idle, loss of power, white or black smoke, warning lights or the engine cutting out. Don’t restart it to “see if it’s OK”.
The longer the engine runs on the wrong fuel, the more likely damage becomes, especially petrol in a diesel. Read what driving with the wrong fuel does.
What not to do
- Don’t top up with the right fuel. Diluting it doesn’t remove the contamination.
- Don’t try to drain it yourself. Petrol vapour is a fire risk and contaminated fuel is a regulated waste.
- Don’t drive “just to the mechanic”. A few kilometres can be enough to damage a diesel fuel pump.
- Don’t wait for it to “settle”. Petrol and diesel mix, so there’s nothing to separate out.
What to tell the fuel drain service
- Your exact location (servo name, pump number or address)
- Vehicle make, model and year
- Which fuel went in, and roughly how many litres
- Whether the engine ran or the ignition was turned on
- Anything unusual, like a second tank or a trailer
Find a service near you
Mobile wrong fuel services listed by state, so you can call someone local.
Common questions
I've already started the engine. What now?
Switch it off as soon as it’s safe and don’t restart it. A drain is still usually the fix, often with a fuel filter change. Tell the technician how long it ran.
Do I need a tow truck?
Usually not. A mobile fuel drain service works on site. A tow only makes sense if no mobile service covers your area or the car is somewhere unsafe to work.
Will roadside assistance fix it?
Most roadside patrols don’t carry fuel drain equipment. They can make you safe and arrange a tow, but the drain is usually done by a specialist.
How much will it cost?
A standard car usually costs a few hundred dollars for an on-site drain if the engine hasn’t run. See our cost guide.
Want to understand what happens inside the engine? Read understanding misfuelling, or learn how to stop it happening again.