We’ve all heard the stories via the grapevine of the typical motorist pulling up at the petrol station and the petrol attendant inadvertently putting the wrong fuel into their car. This, quite surprisingly, is quite a common mistake made in South Africa according to my local garage owner who confirmed they have had at least a dozen incidents.
Of course this mistake is easier to make when accidentally putting petrol into a diesel car. This is because the filler nozzle for petrol is small and narrow vs. a slightly thicker nozzle for diesel. As such it would be difficult to get a diesel nozzle into a petrol car whereas a petrol nozzle would fit comfortably into a diesel car’s filler spout.
The immediate reaction would be to have the car towed away into the dealer for the fuel tank to be emptied… that is to say if you actually have noticed that the wrong fuel was used in the first place. But what happens if you don’t? Would your car be irreversibly damaged resulting in a huge repair bill?
According to the 5th Gear video below it would seem that cars unfortunate enough to have been filled up with the wrong fuels don’t seem to suffer too much, except of course for the expected detonation and pinking that occurs, but it would obviously not be advisable to try this on your own car or take it for granted should this mistake occur.
The diesel/petrol in the opposite car’s tank will eventually work its way through the system and allow the car to function as normal but what the video doesn’t highlight is the potential damage that has already been done which could affect the car in the long run. The video shows two slightly older cars and it is advised that in newer cars, with less tolerance due to technological advancements, this should NOT be attempted. Regardless of the age of your vehicle, however, catastrophic damage can occur to the engine, fuel and exhaust systems by using the wrong fuel so the best advice would be to have the fuel tank drained by your manufacturer or a trained professional.
This study is interesting for all the inquisitive petrol/diesel heads as you get to see just how these cars behave whilst attempting to run them on the opposite fuel their engines were designed for.