What happens if you put petrol in diesel car
It’s a heart-sinking moment every driver dreads: realising you've put petrol in a diesel car. This is one of the most serious and costly mistakes you can make at the pump, with the potential for catastrophic engine damage.
The most important thing to remember? Do not start the engine. That one simple decision can be the difference between a straightforward fix and a bill for thousands of pounds.
The Critical Mistake of Fuelling a Diesel Car with Petrol
To really understand why this is such a disaster, you need to know a fundamental difference between the two fuels. Diesel isn't just for combustion; it's also a thick, oily lubricant. It’s designed to coat and protect all the intricate, high-pressure components of your car's fuel system.
Think of your fuel pump and injectors like a high-performance Swiss watch. Every moving part relies on the lubricating properties of diesel to operate smoothly under incredible pressure. Petrol, on the other hand, is a solvent. When it hits your diesel system, it starts to strip away that vital, protective oily film.
With around 10.96 million diesel cars still on UK roads in mid-2024, misfuelling is a persistent and expensive problem. In 2023 alone, it led to thousands of breakdown calls, with average repair bills falling anywhere between £500 and £2,500, all depending on how bad the damage was.
