Putting petrol in a diesel car can cause serious and expensive damage in a short amount of time. The friction caused by petrol in a diesel engine increases the friction between parts, which is not good news for the engine. The longer a diesel car runs on petrol, the worse the damage gets. However, if you realize your mistake at the pump, mixing petrol in diesel fuel isn’t the end of the world. You will need to get your cars fuel tank drained, but the real damage can occur when you drive away, which could end up costing you thousands of pounds. If you have already set off and realized that something is wrong, pull over and turn the engine off as soon as possible to avoid doing any further damage. Here are some steps to follow if you put petrol in a diesel car:
- Dont start the engine: Starting the engine can circulate the petrol around the engine and cause more damage.
- Call for help: Call a professional service like NRMA roadside assistance or a mechanic to drain the fuel tank and flush the fuel lines and engine.
- Avoid driving the car: If you have already started or driven the car, stop it safely as soon as you can and turn off the engine.
It is generally much more difficult to put the wrong fuel in a petrol car due to the diesel fuel pump nozzle being much larger than a petrol nozzle. However, if you do manage to put diesel in a petrol car, it is far less serious than putting petrol in a diesel car. Diesel in a petrol engine is less likely to result in any permanent damage, but you still want to avoid circulating fuel around the engine if possible. The reason it is less damaging is that petrol engines use spark plugs to ignite the fuel, while diesel is ignited through compression. If you notice the mistake while refuelling or before putting the key in the ignition for the first time after filling up, the fuel tank will need to be drained and flushed[[1]](https://www.autoexpress.co.uk/car-news/95327/wrong-fuel-a-guide-on-what-to-do-if-you-put-petrol-in-a-...
