Misfuelling: the costly car mistake you never want to make
Ever filled your car with the wrong fuel? What to do if you make this common mistakeDeciding between a Maxibon or Magnum Classic at the service station could be the split second lapse in concentration it takes to put the wrong fuel in your car; a common mistake made by thousands of Aussies every year, according to the latest research.
Novated Lease Australia has revealed the costly mistake is more common than many of us might think, with around 7500 “misfuelling” incidents reported Down Under each year.
And it ends up costing Aussies a whopping $10 million (estimated) in repairs each year.
Google Trends data that monitors the search phrase “petrol in diesel” would suggest misfuelling is most common in the Northern Territory, followed by Western Australia, and Tasmania and the ACT in equal third.
It’s a little less common in South Australia, Queensland and NSW, with Victoria showing the lowest search volume for the same phrase.
Maybe there’s some truth to slogan brandished on Victorian registration plates: “the education state”.
Nevertheless, here’s what to do if you put the wrong fuel in your car.
According to Novated Lease Australia, the best-case scenario is realising you’ve misfuelled your car before switching on the ignition because once the incorrect fuel has made its way to your engine, repair costs can skyrocket.
What should I do if I’ve put the wrong fuel in my car?
- Stop fueling immediately and do not start the engine
- If you realise you've misfuelled before starting the car, you’re in a fortunate position to prevent extensive damage. If you're at a fuel station, push your vehicle away from the pumps to avoid obstructing others and to allow easy access for assistance
- Call for help. This might be your insurer if misfuelling is included in your policy, your breakdown provider, or a professional roadside assistance service that can safely drain the incorrect fuel. Attempting to drive or even start the engine can cause severe damage, leading to costly repairs. It’s essential to act swiftly and avoid taking any risks that could exacerbate the situation
What if I’ve already started the car after putting the wrong fuel in?
- Immediately turn off the engine and pull over to a safe location, as continuing to run the engine can cause the wrong fuel to circulate, potentially damaging components like the fuel injectors, pumps, and filters
- Once you’re safely parked, contact a professional roadside assistance service right away. They will need to drain the incorrect fuel from the system and may need to flush the fuel lines and engine to prevent further damage. It’s crucial to avoid driving the vehicle any further, as this could lead to more severe and costly repairs
Putting petrol in a diesel-powered car is much more common because the petrol nozzle is smaller and will easily fit inside a diesel tank, while a diesel fuel nozzle is larger in diameter and usually won’t fit in a petrol car. Even still, here are some signs to look (and listen) for, according to Novated Lease Australia.
Signs of petrol in a diesel car:
- The engine may not start or could stop abruptly
- You might hear loud knocking or banging noises when you accelerate
- Excess smoke could be coming from the exhaust
- There could be a loss of power when accelerating
- The engine warning light might illuminate
This type of misfuelling can cause significant damage, especially if you switch on the ignition.
When you turn the key, the dashboard lights may illuminate, which could activate the fuel pump. Instead of priming the engine with diesel, your car will start drawing petrol through the fuel lines. This contaminates the system, requiring the fuel tank and lines to be drained and flushed.
If you start the engine, the situation becomes much worse. Diesel acts as a lubricating oil, ensuring that engine parts run smoothly, minimising wear and tear. However, petrol mixed with diesel acts like a solvent, dissolving this lubricant. This increases friction between engine parts, which can cause severe and costly damage.
Signs of diesel in a petrol car
- The engine may not start
- Smoke could be coming from the exhaust
- The engine might misfire or run roughly
In the event that diesel is mistakenly introduced into a petrol tank, the consequences, while still problematic, are generally less severe than when petrol is introduced into a diesel engine.
Diesel’s lubricating properties cause it to coat the spark plugs and fuel system components, often leading to issues such as misfiring, excessive smoke, and an engine that either fails to start or stalls shortly after starting. If you realise the mistake before turning the key, it is essential to have the fuel tank drained and flushed immediately. Once this is done, the tank can be refilled with petrol, and the vehicle should function as normal.
However, if the engine is started, the situation escalates. Diesel fuel will cause soot to accumulate rapidly on the spark plugs, leading to clogged fuel injectors and a subsequent loss of engine power. In such a scenario, not only will the fuel tank need to be drained and flushed, but the fuel lines, spark plugs, fuel filter, and injectors will also require thorough inspection and potentially cleaning.
Related: What should I do if I run out of fuel?
Related: Your questions answered: What fuel should I use and how can I save money?
Related: What do the numbers on fuel pumps mean?
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