What to do if you’ve filled up with the wrong fuel
You have somehow managed to put the wrong fuel into your car, don’t worry, these things happen. But, whether you’ve realised your mistake 30 seconds in or not until you’ve brimmed the tank it makes no difference, the result is the same and the entire fuel tank will need to be drained.
It’s important that, no matter what else you do, you don’t start your car. See, by not starting your car you can keep the ‘wrong’ fuel in the fuel tank, thus making the fix a little simpler and less expensive. But, should you start your car before realising you’ve filled it with the wrong fuel, well, then you’re in a whole world of trouble as the ‘wrong’ fuel will mix and begin to circulate around your vehicle, more on this shortly.
So, if you’ve realised your mistake and haven’t started the car, return the pump to the bowser and head inside and tell the fuel station attendant what you’ve done that. Hopefully they’ll have seen this before and be sympathetic. And, hopefully, if you’re on your own, they’ll help you to push your car to one of the car parks at the petrol station. From there you can call ROAD HELP and tell them what you’ve done, they will draining the tank and get you going again.
But, if you’ve started the vehicle and driven a short distance before realising your mistake, well, you’ll need to have your vehicle towed to a mechanic for a thorough check over. And this is where the costs can mount, as it’s likely you’ll be up for a new fuel tank, new fuel lines, fuel filters and fuel pump(s) and injectors – although this really does depend on the vehicle and the circumstances.
And, if your vehicle is still under warranty when this has occurred you’ll need to let the dealer where you purchased the vehicle know what’s happened as misfuelling, and subsequent damage caused by it, isn’t covered by either your warranty or insurance. They might even request that the vehicle be towed to them for the work to be carried out.
Why is it a problem if I put petrol into my diesel vehicle, and vice versa?
Firstly, and in case you didn’t already know, diesel and petrol are different. Yes, they’re derived from the same base petroleum product (although diesel can also be produced from vegetable oil – bio-diesel), but the chemical structures of the end products are different. As are the engines and how they convert the chemical energy from the fuel into mechanical energy.
So, the engines work differently and that’s because the fuels behave differently. See, petrol is essentially a solvent and, so, when it’s tipped into a diesel engine strips away the oily coating that diesel provides to a diesel engine (diesel acts as a lubricant).
It means, that with this protective coating washed away the seals will dry out and crack, and because of the metal-on-metal friction the engine will likely overheat, seize up and fail. Thus putting petrol into a diesel engine can become an expensive mistake.
If you do it the other way around and put diesel into a petrol engine then the main problem you get is that the oiliness from the diesel will coat everything inside the engine and because diesel doesn’t burn very well and burns slowly at that (it requires a high compression ratio to create the necessary ignition), a spark plug will be fairly ineffective at igniting a puddle of diesel in the cylinder and so you’ll end up with a coughing, smoking mess.
So, putting diesel into a petrol engine and then starting it up will be a problem and require a lot of stuff to be replaced, but running petrol in a diesel engine will cause a more dramatic failure of the engine. Some technicians report it takes twice as long to sort out a diesel engine that’s had petrol run through it than diesel in a petrol engine.
There’ll be some out there running bio-diesel, but the amount of people doing this is likely to be small and given you can’t find it at your local petrol station we’ll ignore it as a potential issue and stick with petrol and diesel (that can be purchased from a petrol station) only.
