A critical warning has been issued to UK drivers who risk causing catastrophic and expensive damage to their vehicles by making a simple but devastating mistake at the fuel pump.
The Costly Error Happening Every Three Minutes
Known as misfuelling, the act of putting petrol in a diesel car or diesel in a petrol vehicle is a surprisingly frequent error. The RAC states this mistake occurs approximately once every three minutes in the UK. It often happens when drivers are distracted or using a different vehicle to their usual one.
While it may seem like a simple slip, the consequences are far from minor. The repair costs can escalate rapidly, especially if the engine is started. "Misfuelling repairs can easily cost hundreds or even thousands of pounds," explained Kerry Fawcett, a spokesperson for vehicle services company Radius.
Why Wrong Fuel Causes Catastrophic Damage
The severe damage stems from the fundamental differences in how petrol and diesel engines operate. Diesel engines rely on compression ignition, while petrol engines use spark plugs.
When petrol is introduced into a diesel engine, it acts as a solvent, stripping away the lubricant that keeps the high-precision fuel pump and injectors functioning smoothly. This immediate loss of lubrication causes intense friction between metal components, leading to misfiring, scoring, and, in the worst cases, complete engine seizure and failure.
The scale of the repair depends entirely on whether the ignition was turned on. If the driver realises the error before starting the car, the fix typically involves draining the tank, cleansing the fuel lines, replacing filters, and refilling with the correct fuel.
However, if the engine is started, the contaminated fuel circulates throughout the entire system. This often means the fuel pump, injectors, and other components must be completely replaced—a bill that runs into the thousands. For larger vehicles like HGVs, the costs are even more staggering due to their substantial tank sizes.
What to Do If You Misfuel Your Vehicle
Motor organisations stress that the immediate action is crucial. Do not start the engine or turn on the ignition. If you have already done so, switch off the engine immediately.
The RAC offers a dedicated wrong fuel recovery service for such incidents. "Our fuel patrols are trained mechanics and hold accreditation to allow them to work safely on petrol station forecourts," the organisation said. Their service involves draining the tank and fuel system of the contaminated fuel and providing enough clean fuel to get you moving again. For more severe cases, they can arrange for the vehicle to be towed to a garage.
The key takeaway for all drivers is to stay focused at the pumps. Taking an extra moment to double-check you have the correct fuel nozzle could save you from a repair bill running into thousands of pounds and the significant inconvenience of a broken-down vehicle.
