Important: If you’ve used the wrong fuel, do not switch the engine on!
Putting the wrong fuel in your car is an easy mistake to make. It is also really easy to stop your mistake from costing you thousands … by doing nothing.
Attempting to siphon the fuel out of the tank is not recommended as you won’t be able to remove all of the fuel from the tank. And by doing so you could also be putting your safety or the environment at risk.
If you start your car, or drive away before you realise your mistake, stop somewhere safe as soon as you can. Switch the engine off to minimise damage.
What happens when you put petrol in a diesel engine?
Putting petrol in a diesel car can cause serious damage to the fuel injection system and the engine.
As well as powering the car, diesel acts as a lubrication oil that keeps the fuel pump and other components running smoothly. Petrol, acting as a solvent when mixed with diesel, has the opposite effect.
Adding petrol to a diesel engine increases friction between parts, causing damage to the fuel lines and pump. If you drive away or even start the car with petrol in the mix, you could cause expensive damage to the engine.
If you realise that you’re putting petrol in your diesel car while still at the petrol bowser, it’s recommended that you stop and call roadside assistance. Starting the engine will cause the fuel to circulate through the system. This will cause further contamination, so to keep damage to a minimum stay away from the ignition.
What happens when you put diesel in a petrol engine?
Inadvertently putting diesel in a petrol car is more difficult to do because diesel bowser nozzles are deliberately larger than petrol ones.
The result of putting diesel in your petrol car is not quite as catastrophic as when it’s the other way round. The car will usually run roughly and the exhaust will be smoky. In addition, damage to the fuel injectors may occur, particularly if you’ve started the engine and driven away.
What to do if you’ve put the wrong fuel in your car
First of all, and this is most important: Do not start your engine!
If you’ve realised your mistake before starting the engine, here’s what you do:
- Tell the petrol station what’s happened
- Don’t start the engine – Put the car in neutral
- Have someone help push your car to a safe place
- Call your insurer as soon as you can to see if you are covered for misfuelling
- Have your vehicle towed to your local mechanic
If you don’t realise your mistake before you drive off, your car will let you know soon enough, as the engine may start making unusual noises, or you could experience a sudden or complete loss of power. If you find yourself in this situation, quickly find a safe place to pull over and call for assistance.
How can I avoid putting the wrong fuel in my car?
Paying attention when you swing into the petrol station the only way to avoid ruining your car and your day. This advice is especially relevant to those who are driving a hire car or have borrowed a car as you may be unfamiliar with what fuel is used. So always take a moment and be sure before you fill up.
It should also be noted that any damage done to your car as a result of putting the wrong fuel type in isn’t covered by warranty. Your insurance may not help either. This means that it can really cost your back pocket. So, like any other time you get behind the wheel, it pays to stay alert.