Frequently Asked Questions
Wrong Fuel in Your Car? Get the Facts Before You Panic!
I accidentally filled my diesel car with petrol and drove for 2 miles before it stalled. Does it need repairs?
You didn’t actually drive 2 miles on petrol; instead, petrol mixed with the remaining diesel in your tank. The engine likely stalled after about 20 yards—once petrol fully replaced the diesel in the fuel system. While misfuelling can cause various issues, it’s not always disastrous. A mobile fuel drain can fix the problem quickly, and our service is available nationwide, typically arriving within 50 minutes, 24/7. Below, I’ve outlined common misfuelling scenarios.
What does petrol do to a diesel car's fuel system?
Petrol in a diesel car disrupts the fuel system by reducing lubrication, which can cause excessive wear on fuel pumps and injectors. Diesel engines rely on fuel for lubrication, and petrol’s lower viscosity increases friction, leading to potential damage. It also affects combustion, causing misfiring, loss of power, and eventually stalling. If not addressed quickly, prolonged running can damage components like the high-pressure pump and injectors. The best solution is to stop the engine immediately and get a fuel drain to prevent further harm.
What happens to the drained fuel after removal?
The drained fuel is stored in licensed containers before being collected by a specialized waste management company, similar to those handling used oil and other automotive fluids. Across the UK, thousands of liters of mixed fuel are gathered weekly. Once enough is accumulated, it is sent to a refinery for processing. Through distillation, petrol and diesel are separated at specific temperatures, ensuring proper refinement. The reclaimed fuel is then likely reintegrated into the supply chain for reuse.
Will putting the wrong fuel in my car cause damage?
It’s unlikely. Most vehicles run fine after being drained. If you haven’t started the engine, there’s no harm done. If you’ve driven it and the car stalled, permanent damage is rare. Diesel cars won’t run long enough on petrol to cause serious harm.
My car stalled after misfuelling. Is it ruined?
No. A stalled engine is just preventing further damage. Once the incorrect fuel is drained, fresh fuel added, and the system purged, the car should run as normal.
Which is worse—petrol in a diesel car or diesel in a petrol car?
Both cause problems but in different ways. Petrol in diesel can damage the high-pressure pump if driven for a long time. Diesel in petrol can contaminate the oil system, potentially leading to severe engine failure. However, such extreme cases are rare.
How can I prevent misfuelling?
Diesel drivers can install a special filler cap that blocks petrol nozzles. Unfortunately, there’s no similar device for petrol cars yet. Staying mindful at the pump is the best prevention.
Why is petrol added to diesel in cold climates?
In extreme cold, petrol can be used to prevent diesel from thickening, but modern diesel already contains winter additives. This practice is outdated and not recommended for today’s engines.
Do I need a new fuel filter after misfuelling?
No, unless it’s already due for replacement. Some garages use this as an excuse to charge extra. A proper fuel drain will remove contaminants without needing a new filter.