Filled the Wrong Fuel? Here’s What You Should Do – Fast!


Sep 07th, 2020


Filled the wrong fuel in? Filling petrol into a diesel engine vehicle is a classic gas station error. Don’t be so cast down now. To err is human. To rescue from error, however, is CARPARTly, so we’ve come to save the day. Below is what to do next after the deed - filling in the wrong fuel - is done. 


Have you turned the ignition yet? If not, don't try to! The damage that comes from putting in the wrong fuel occurs after turning on the ignition. If you haven't started your engine yet, the wrong fuel remains mostly in the fuel tank—it hasn't been flowed through the pipes into the combustion chamber. At this stage, you can drain off the fuel with relative ease.

So, if you realise you've filled in the wrong fuel before starting your vehicle, here's what you should do:

1. Don’t switch on the engine. To be on the safe side, remove the key from the ignition.

2. Inform the gas station staff about what had just happened; there might be services in place to cater for such incidents.

3. Engage the neutral gear.

4. Ask for help to push the vehicle to a safe place; somewhere accommodating and free from fire (where you can have the fuel drained).

5. Call to inform your car insurer as soon as possible.

6. Call a breakdown cover; they ought to have the option to drain, flush and refuel your vehicle.

What Should You Do If You Started Your Engine after Putting the Wrong Fuel?

If you aren't so fortunate and you started the engine before realising what had happened, here's what you should do: 

1. Turn off the engine ASAP and pull over to a safe spot.

2. Change gear to neutral.

3. Call a breakdown cover to drain and flush your engine.

4. Call your insurer as soon as possible.

Symptoms of Mis-fuelling

Contemplating! Probably, you are not even sure that you had filled in the wrong fuel. Well then, here are a few signs to look out for. If you've filled and used diesel in a petrol engine, you might notice:

  • Your engine misfiring
  • Excessive smoke from your exhaust
  • Engine stops working
  • Engine not starting

If you’ve filled and used petrol in a diesel engine, you might notice:

  • A loud knocking noise while accelerating
  • Excessive smoke from your exhaust
  • Vehicle not accelerating, slower than usual
  • Engine warning light blinking
  • Engine stops engine
  • Engine refusing to restart

What Happens If You Pumped the Wrong Fuel In?

Filling a diesel car with petrol is a far more severe situation than putting diesel in a petrol vehicle. Nevertheless, both situations can cause costly damage to your car. Let's take a peek at what happens in both scenarios:

Scenario 1: Petrol in a diesel vehicle

Diesel engines are designed in a way that they use their fuel also as lubricating oil; this ensures that the engine components run smoothly to prevent wear and tear. When you fill petrol into a diesel engine, there is an increase in friction in the engine as the fuel is not viscous enough to keep the engine running smoothly. This, therefore, damages components, including your fuel lines and pumps.

With this mistake, you could end up running up the cost of a new fuel pump, injector, funnel, channel, fuel tank or even a totally different substitution engine, worst-case scenario.

Scenario 2: Diesel in a petrol vehicle

Like I said already, this could also cause real pain. But, it's certainly not as damaging as putting petrol into a diesel engine. After starting the engine, the diesel clots or coats the spark plugs and fuel pump, most times causing engine misfire. The engine will also give off excess smoke, cut out, and fail to start after a while.

Your engine shouldn't have any permanent damage if the fuel is drained out as soon as possible.

Finally, I understand that nobody is faultless. Still, you want to avoid putting in the wrong fuel in your car altogether. To avoid that possibility, here a few things you should or shouldn’t do; 

1. If you recently purchased a vehicle, consult the owner's manuals before refuelling. When renting a car, be sure to ask what fuel it uses.

2. Avoid refuelling when you are in a rush, cut all interruption and stay attentive if need be to refuel the vehicle

3. Leave visual prompts and reminders. If you tend to get all disorganised like me, you may put a sticker on your fuel cap indicating what fuel should go in.

If you do all these and still forget, well, it's for reasons like this that breakdown covers exist. Use the tips shared above, and you and your car will be fine.

Filled in the wrong fuel? Now you know what to do. Do I hear you screaming “Carpart to the rescue?” 

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By Damilare Olasinde