It happens. We get distracted and think we are acting out of habit, and suddenly we realize we’ve put the wrong type of fuel into our gas tank. You’re not alone. Or maybe you accidentally filled up with the wrong fuel because you didn’t know what type of fuel you were supposed to use—with so many options of fuel out these days, how do we know which one is right for our car? And what will happen to your vehicle and how should you respond if you accidentally fill up with the wrong type of fuel? The answers to these questions will vary depending on what type of fuel your vehicle is supposed to take, what type of fuel you accidentally filled it with, and how much of the wrong fuel was used.
Filling your diesel fueled engine with petrol gasoline is the most serious fuel mistake you can make. If you fill your diesel fueled engine with regular petrol gasoline it is extremely important not to run your vehicle until the fuel system has been completely cleaned out because this can lead to serious damage occurring in your engine. Once you start a diesel engine that has been fueled with petrol gasoline it doesn’t take long for catastrophic failure of the injection pump, the injectors, and finally the entire engine to occur.
Vehicles that have a gas engine are not able to combust diesel fuel. However, putting diesel fuel into a gasoline fueled engine typically is not as harmful as putting gasoline into a diesel fueled engine. If you only put in a couple gallons of diesel, then it may only make the car run a bit more poorly, but if you put too much diesel into a gasoline fueled engine then the vehicle may quickly stop working. Ignoring the problem could potentially cause the fuel pump, fuel lines, and fuel injectors to be ruined, and the fuel filter to get clogged up leading to other damage occurring.
Octane numbers are those numbers you see distinguishing regular gasoline from premium gasoline. You might think that using a premium gasoline even if your vehicle doesn’t call for it will help your vehicle to run better, but the only real difference you will notice will be in the cost to fill up. Fortunately, if you accidentally fill up using premium gasoline instead of regular gasoline, you should not experience any damage to your vehicle either.
Unfortunately, using regular gasoline in a vehicle which requires the usage of premium gasoline is not the same as using premium gasoline in a vehicle that only needs regular gasoline. If your vehicle requires premium gasoline and you do not use it, serious damage may occur—and your vehicle warranty may be invalidated. Vehicles which are recommended to use premium gas may lose performance and fuel economy if regular gas is used and over time, constant use of regular fuel could cause engine trouble.
First, to understand the potential damage that can occur, you need to understand the differences between regular gasoline and premium. Premium fuel typically has an octane rating of 90 or higher. Octane is key to powering vehicles and gasoline with higher octane levels are less likely to pre-ignite (which causes a knocking sound and, over time, with repeat occurrences can cause engine damage).
Your engine’s computers can adjust to lower-octane performance (to an extent) and help limit the amount of damage caused, so if this is only done accidentally one time you will probably notice reduced performance and lowered fuel economy but will not likely experience serious damage from the wrong fuel type. Just make sure you switch back to premium fuel as soon as you can.
It is obviously best to make sure you know what type of fuel your tank requires and pay close attention at the pump to make sure you are using the right type of fuel, but if you accidentally fill your tank with diesel when it requires petrol or vice versa, here are the steps you should take:
If you are still fueling up when you notice your mistake:
If you drive before you notice your mistake:
Most car insurance coverages have a misfuelling exemption clause that will exempt the insurance company from being responsible for any claims resulting from adding the wrong type of fuel to your vehicle. You should check your current policy documents to see if your policy includes this misfuelling exemption clause. Even if your policy does not include this exemption clause, it is unlikely that your insurance company will pay for the cost of having your vehicle towed and professionally drained and flushed out.