If you’ve ever put the wrong sort of fuel in your car, you are not alone. When one member of my family (who will remain nameless*) filled a diesel-powered work ute with petrol the other afternoon, the local garage said that it was the second time it had happened that day.
What happens if you put the wrong sort of fuel in your car? If you drive a diesel and have put petrol in the tank, you’re in real trouble. Petrol acts as a solvent and reduces the amount of lubrication that diesel can do to the engine parts – and diesel engines need that lubrication. The sooner that you realise that you’ve put in the wrong fuel, the better. If you’re still at the bowser when you realise what a nitwit you’ve been, don’t start your engine. The petrol can be drained from the fuel tank (along with everything else in the tank) and the wretched stuff won’t get into your engine and ruin it. If you start the engine – well, there goes your engine! They say that if petrol does get into the workings and start chugging around inside, a whole new motor is going to be cheaper than an attempt to repair it. If the car is on the older side, a whole new car might be in order.
What about the reverse? What if you put diesel into a petrol engine? This is less of a disaster and you won’t kill your engine if you switch the ignition on. What will happen when you switch the ignition on is… not a lot. You see, diesel engines have a lot more compression than petrol engines to get the air hot enough to ignite the fuel. Petrol engines just don’t have what it takes. This is a very short description and there’s a fair bit of science going on here, but let’s stick to the point. Again, you’ll have to get towed away so your car can have its tank pumped out but if a bit of diesel’s got into the system, it isn’t the end of the world. But prepare for some rough running.
Manufacturers of cars and of bowsers have sensibly made the diesel and the petrol nozzles, and the holes they go into, different sizes. Diesel needs a bigger nozzle, so the chances that you’ll shove diesel into a petrol is slim, unless you have an older vehicle. This won’t help you if you try to put petrol into a diesel, as you can fit a small nozzle in a big hole. However, the way the nozzle wobbles around should tip you off.
The expense, hassle and humiliation of having to get a full tank of gas pumped out of your vehicle and chucked away can be avoided by either (a) not going on autopilot when at the bowser if you have two cars with different fuels or (b) getting one of the petrol pump attendants to do it for you. If they make a mistake, it’s their expense and hassle. Besides, you get to talk to a real human being (great after a day behind a computer or making endless phone calls) and ensure that your local garage keeps employing teenagers who would otherwise be making trouble.
*No, this person was not me. I know about this event because I got the call and had to head out with my big Ford Fairlane to tow this person to the mechanics so their car could have its stomach pumped. Family member is getting enough leg-pulls from everyone else so there’s no need to preserve their name for eternity online.