Diesel In Petrol

Putting Diesel in a Petrol Engine

Putting diesel in an unleaded or leaded petrol engine can be bad for the car and should be avoided at all costs. It is worth noting that putting petrol in a diesel is far far worse than putting diesel in a petrol and could seriously damage your engine.

If you have an older car, and have only put a small amount of diesel in (less than 5 litres), then you should just fill the car up with petrol and drive off. The exhaust may be a little smoky but this shouldn’t damage your car. If you accidentally put more than 5 litres of diesel in the petrol tank or drive a modern car then you shouldn’t turn the engine on, and need to call for assistance to drain the tank. If you do start the engine that you may cause more damage and could need engine parts replacing.

Is diesel in petrol a common problem?

Lucky accidentally putting diesel in a petrol engine is very uncommon. The main reason for this is that diesel filling nozzles tend to have a larger diameter than petrol nozzles and so they just won’t fit through the filler cap.

Far more common and damaging is if petrol is added to a diesel car.