What Happens if You Put Diesel in a Petrol Engine

Putting The Wrong Fuel In Your Car

Car fuelling mistakes are common occurrences in Australia. Whether it is filling the fuel tank of a petrol engine car with diesel or putting petrol in a diesel engine, you can easily make these mistakes if you do not pay full attention when at the pump.

While you can do things to avoid damaging the components of your car engine and fuel systems when you put the wrong fuel, these fuelling mistakes can sometimes prove costly as you may need to replace your car's entire fuel system.

In this article, we highlight common car fuelling mistakes, how putting diesel in a petrol engine impacts your car engine components and fuel systems, and what to do when you accidentally put the wrong fuel in your car.

Results Of Putting The Wrong Fuel In Your Car

It's simple. You end up with fuel contamination if the wrong fuel finds its way into your fuel tank. In most instances, fuel contamination in cars results from mixing petrol and diesel by accidentally putting diesel in a petrol engine or putting petrol in a diesel engine.

The most severe damage happens if your fuel tank has the wrong fuel and you turn on your car engine without realizing this mistake. You are, however, lucky if you discover that your fuel tank has been filled with the wrong fuel before you start your car engine.

Common Fuelling Mistakes

Owning an electric car would probably be the only way to escape costly car repairs that result from using the wrong fuels on vehicles. It is not uncommon to realise you have filled your fuel tank with the wrong fuel minutes after driving away from the pump.

While some people end up with the wrong fuel in their car tanks because they are unfamiliar with the correct fuel for their car, this is not always the case. Sometimes it is because you just picked the wrong fuel nozzle due to stress or some sort of pressure.

The following are some of the prevalent mistakes people make while putting fuel in cars:

• Putting diesel in the petrol tank and vice versa. Using diesel in a petrol engine may not be as consequential as using petrol in a diesel engine.

• Putting diesel in the gas tank and vice versa

• Using the wrong grade of fuel

Petrol, gasoline, and diesel differ in their features, power generated, and functionality in engines. It is advisable that you use the right car fuel in the right engine. While some mistakes, such as using gas with higher octane ratings in a car that does not need it, only waste your money without hurting or boosting your car engine performance, some, like putting petrol in a diesel engine, can leave you with high repair bills.

Putting petrol in a diesel engine

It is pretty easy to accidentally put petrol in diesel tanks of vehicles with large filler necks that accept petrol nozzles. While operating, diesel fuel pumps are lubricated by diesel fuel. When petrol and diesel mix, the lubrication properties of diesel reduce.

The resulting friction from metal-to-metal contact damages the fuel pump, while the metal particles are created to damage the other components of the fuel system. Repairs that include the replacement of the entire fuel system can be costly.

Because diesel engines operate under a higher compression ratio, serious engine damage may occur due to misfiring resulting from uncontrolled petrol ignition under the much higher compression ratio in diesel engines.

When petrol is used in diesel engines, the following are the likely outcome:

• You will hear a loud knocking sound while accelerating

• Excess smoke coming from the exhaust

• Your acceleration will be slower than usual

• You will see the engine warning light illuminating

• Difficulty in restarting the car or engine will stop altogether

While fuel systems of newer versions of diesel engines are damaged by even the most minor levels of fuel contamination because they operate on very tight tolerances, older diesel vehicles and stationary diesel engines that run farm machinery can tolerate small amounts of petrol contamination.

Using petrol in diesel engines is far worse than using diesel in petrol engines.

Putting diesel in a petrol engine

Putting diesel in petrol tanks by accident is more difficult because diesel nozzles are larger than petrol nozzles and hence may not fit into the filler necks of most petrol cars. If a mistake happens and diesel finds its way into petrol engines, the consequences are always less severe than what happens when petrol finds its way into diesel engines.

When you accidentally put diesel in a petrol engine and switch on the ignition, the diesel will coat the spark plug, which often leads to the following:

• Misfiring in the engine

• Cut out

• Engine failing to start

• Excess smoke coming from the exhaust

Using the wrong fuel grade

High fuel prices may make you consider using cheaper fuel grades for your car. For example, gasoline has three grades with varying performance and costs. These include regular, mid-grade, and premium/super.

Using regular grade fuel in a car that requires premium or super grade will have the following consequences:

• Rattling noises in your engine

• Decreased fuel economy

• Reduced efficiency and engine performance

Using premium fuel in a car that performs just well with regular fuel is only a waste of money as it doesn't boost your engine's performance. Also, there will be no damage to your car if you use higher octane gas in a vehicle that does not need it. Always select the correct octane rating for your car. Your car's minimum octane rating is found in the owner's manual.

Solutions If You Put The Wrong Fuel In Your Car

Sometimes when you have pressure to complete essential tasks and little time to fuel your car, you may not pay full attention to the pump and end up picking the wrong fuel nozzle. You will undoubtedly end up with the wrong fuel in your car fuel tank when this happens. If you have no idea as to what to do with the wrong fuel in your tank, the consequences can be dire.

Never panic if you have accidentally filled your fuel tank with the wrong fuel. The tips provided here can help you minimise car damages associated with fuel contamination.

Before starting the engine

Take the following actions if you discover before turning on the ignition that you have put the wrong fuel in your car:

• Do not start the engine or even put the car key in the ignition

• Put the car in neutral

• Inform the pump attendants of the fuel mishap

• Seek help from wrong fuel rescue experts to drain and flush your fuel systems

• Inform your insurance provider as soon as applicable

After starting the engine

Sometimes you never realise you have filled your tank with the wrong fuel until you turn on the ignition. Here is what to do if you have started your car engine with the wrong fuel in the tank:

• Pull over safely once you realise and turn off the engine

• Put the car in neutral

• Seek help from wrong fuel rescue experts to drain and flush your fuel systems

• Inform your insurance provider as soon as applicable

Sometimes you realise in the middle of fuelling your car that you are actually putting the wrong fuel in your vehicle. If, for example, while filling your petrol tank you realise the mistake after putting diesel into less than 5% of the total tank capacity, it is safe to fill the rest of the tank with petrol and drive without any problem.

This is because diesel easily mixes with petrol. It is, however, advisable that even if it is only a tiny amount of diesel contamination, you should drain your tank.

After driving for some time

Of all the scenarios, this is the worst case. It is probable that you may not discover that you have filled the wrong fuel in your car until you hit the road. Immediately after you realise you have the wrong fuel in your car while on the road, safely pull over and switch off the car's engine.

If you have roadside assistance cover, call your provider or call a towing service to help move your car to the closest service station. While at the service station, consider having your fuel tank and fuel lines drained to remove residual contaminated fuel. Refill your car with the correct fuel and drive without any worries.

Remember, diesel cars are not as forgiving as petrol cars. Suppose you turn on the ignition and drive your diesel car for some time before realising you put petrol in the car instead of diesel. In that case, the petrol has likely already been pumped into every part of your car engine. If this happens, you are likely to end up with hefty repair bills.

Prevent Putting The Wrong Fuel In Your Car

It is common to put the wrong fuel in your car. You can follow these tips to prevent fuelling mishaps:

• Find other clues apart from relying on the colour of the nozzle

• Read the pump's trigger label and fuel grade carefully

• Using reminders like a having a sticker inside the fuel cap can help prevent fuelling mistakes

• Avoid distractions like using your phone, and pay full attention while at the pump

• Avoid fuelling your car while you have work pressure, are hungry, or are stressed. You are likely to end up with the wrong fuel in your car fuel tank under such circumstances.

• If you have a diesel car, buy a stopper to prevent the narrower petrol nozzles from fitting in your filler neck

When To Contact A Professional

When you realise you have put the wrong fuel in your car, there are insurance, fuel drain, and wrong fuel recovery service providers in Australia that can help you. Whether at fuel stations or even when you realise the mistake while on the road. They help to expertly drain the contaminated fuel from your car fuel tank and fuel system, cover repair bills and provide enough clean fuel to get you moving.

Contact a car buying and selling company if you want to prevent the uncertainty of putting the wrong fuel in your car but do not know which insurance or fuel recovery service provider to approach. These companies can link you with one of the many insurance and recovery service providers in their network.

Also, if your car is highly damaged because of putting the wrong fuel and you wish to sell it, you can use the same company to help you find a buyer easily.