What happens if you use the wrong fuel?


It’s something probably all motorists have done: made a stop at the petrol pumps only for your mind to go completely blank and begin questioning whether you should be filling up with either petrol or diesel. Like most, however, you probably come to your senses and remember just in time. Still, what’s the worst that could happen should you accidentally use the wrong fuel?

First of all, should it be too late and you have already filled your vehicle with the incorrect fuel type, you should refrain from starting your engine. Instead, you should look to contact a vehicle recovery service and have them assess the situation. After all, the damage that can be caused is significant.

Putting diesel into a petrol vehicle

Vehicle manufacturers have made a point of ensuring that diesel pumps don’t actually fit into petrol tanks, thereby reducing the potential risk of such an incident occurring. Should you somehow manage to fill your petrol vehicle with diesel, however, it’s worth being aware of the potential risks.

Diesel fuel differs from petrol in that it needs to be compressed before ignition, whereas petrol ignites through spark plugs. As such, the result of putting diesel into your petrol car will often simply result in the vehicle not starting.

Putting petrol into a diesel vehicle

The more common of the two mistakes, putting petrol into a diesel engine can also be far more catastrophic. Unlike petrol, diesel acts a lubricant and works to ensure the pump runs effectively. Petrol, however, acts as a solvent. When the two are mixed, the opposite effect to diesel lubrication occurs, with the level of lubrication reduced and the resulting effect being increased friction that damages the pump and the engine.

How to avoid misfueling

While it may be a common mistake for motorists to make, putting the wrong fuel into their vehicle is often a mistake that is only made once! However, if you’re concerned that you may be susceptible to committing such an error, there are ways to avoid it happening:

  • Leave yourself a reminder of the correct fuel to use. This may even be a note on your petrol cap.
  • Always check the pumps at your garage before fueling. While diesel pumps are often black and petrol green, there will always be instances where this differs, not least if driving overseas.
  • Try to avoid filling up your vehicle at stressful times. Being worked up can cloud your judgment and cause mistakes to be made. As such, go to the petrol station with a clear head to avoid such pitfalls.

For more details on safer driving, contact the team at Carwise Group in Harlow and Maidstone.