From fuel life to getting the most out of a tank, our Car Doctor can help

Fuel

Is there a right way to fill up the tank for maximum fuel efficiency?

The most effective way to improve the fuel efficiency of your car is to change the way you drive it, such as accelerating more gently and keeping your speed constant when travelling in a steady stream of traffic. How you fill your vehicle’s fuel tank will have little effect on its fuel efficiency – you should simply run it down to approximately a quarter full, and then refill it until the fuel bowser automatically cuts out.

Who checks the accuracy of fuel pumps?

It is the responsibility of the fuel pump owner to ensure their pumps are dispensing accurately. Fuel vendors must comply with the National Measurement Act and will have their pumps checked, calibrated and verified by licensed technicians as part of programmed maintenance. The National Measurement Institute (NMI) has overall responsibility for this legislation and its inspectors conduct regular audits throughout Australia on measuring instruments like fuel pumps. They will also follow up on complaints made about fuel delivery volumes. They can be contacted on their hotline number - 1300 686 664, or by email.

Is fuel consumption helped by using cruise control?

Naturally, fuel consumption can be affected by changing the position of the throttle regularly. On a long trip, where the vehicle’s speed can be kept constant, cruise control is useful in reducing fuel consumption because it helps keep the throttle at a constant opening. When there is a need for a change in throttle, this typically takes place more gradually than would be the case without cruise control engaged. On flat roads, this generally results in better fuel consumption. In hilly areas, intervention by the driver is often required to maximise fuel economy because drivers can usually make better use of the vehicle’s momentum.

What is the danger of refuelling while the engine is running?

There are a number of reasons why you should turn your vehicle off while refuelling. A petrol-run car’s ignition system can run voltages of up to 45,000 volts. A catalytic converter, which is exposed under the car, can reach temperatures of 900 degrees Celsius. Petrol is explosive, and can be ignited with the slightest spark, and even if you don’t spill any fuel yourself, any other fuel spillage at the service station has the potential to be ignited by a running vehicle. For the safety of others around you, always switch off your vehicle’s engine when refuelling.

Can fuel degrade, such as from 98 RON to 95 RON, over time?

Fuel does degrade after a period of time. How fuel is stored will determine how quickly the fuel will degrade. The octane rating will decrease and other additives that are added to enhance the fuel will also degrade. This includes corrosion inhibitors, metal deactivators and any cleaning agents. Fresher fuel will be a better quality. We recommend not using any fuel that has been stored for longer than four months.

What should you do if you accidentally put petrol in your diesel vehicle?

If you have put petrol in a diesel vehicle and you have started the engine, switch the engine off immediately and get the vehicle towed to a licensed repairer to have the fuel tank and fuel system drained and checked for any engine damage that may have occurred. If you have put petrol into a diesel vehicle and have NOT started it, do not turn on the ignition or start the vehicle as this will prime the system and possibly increase the cost of rectifying the problem. Get the vehicle towed to a licensed repairer to be drained and checked. If the vehicle is not started or primed, there is less chance of damage.

What is the difference between truck diesel and normal diesel at fuel stations?

Truck diesel is the same as regular diesel, however there is a very good reason for you to not use these pumps. Most pumps labelled as being for trucks are high-flow, meaning the nozzle is likely to be too wide to fit in your vehicle’s fuel filler neck.

Secondly, as it has been designed to fill high capacity truck tanks, the diesel will come out of the pump much more quickly than a pump designed for light vehicles.

For both reasons we would recommend sticking to the regular pumps for light vehicles.

How reliable is instantaneous and average fuel consumption on the car's display?

While the information provided by your vehicle’s trip computer is always indicative, generally this information is reasonably reliable. However, the vehicle’s instantaneous fuel consumption will vary as the loads on the engine change. Even in cruise control, as the vehicle seeks to maintain speed as the road conditions change, it is likely you will see changes in instantaneous fuel consumption.

Fuel

Fuel

About RAC

RAC Products & Services

Information & advice

Fuel

Fuel

Related Articles and Learns

Car Doctor

Fluids

Car servicing

Related products

About RAC

RAC Products & Services

Information & advice