Misfueled your vehicle? Here’s what to do
The nightmare of your car engine needing to be completely stripped and rebuilt because the wrong fuel was used is a familiar terror to any diesel car owner who has accidentally filled their car with regular petrol.
Surprisingly, it’s actually one of the most common mistakes diesel drivers make, and the AA and RAC both claim that 150,000 drivers make this costly mistake every year. It is less common for petrol car owners to fill up with diesel, partly because the pump nozzle is too large and won’t connect with a petrol powered car.
Another possible cause of driver error could be that petrol pumps typically have green or yellow coloured handles, and all of the advertising we see is for regular unleaded so our subconscious minds could automatically make the connection.
Unfortunately, petrol and diesel are not the same, and petrol being injected into a diesel engine will destroy it fairly quickly.
Petrol vs Diesel Engine
Looking under the bonnet, petrol and diesel engines might appear similar but the way they use fuel is very different.
Diesel engines are machined to operate within very fine tolerances, and their fuel pumps are highly pressurised. More than that, diesel fuel lubricates the inner workings of the fuel pump. The variety of diesel engine used in many modern cars, the common rail or HDi engine, is even more badly affected by incorrect fuel.
Petrol contains ingredients that act as solvents when run through a diesel engine fuel pump, quickly removing residual lubrication, and resulting in the metal parts rubbing against each other. At high pressures, this rapidly results in destruction, sending small metal filings at high speed into the rest of the engine.
The damage that petrol can cause to diesel engines is quick, and within a few miles of petrol entering the fuel pump can already be devastating to the fuel pump. Keep driving and the entire engine could also need to be replaced.
What to do if you’ve misfueled your vehicle
As soon as the mistake is realised, stop everything. If you are still filling the tank, stop, and immediately call for assistance to remove all of the fuel from the car’s tank.
Whilst older diesel vehicles can run on a diesel/petrol mix, this is not recommended and certainly not for any diesel car built in the last decade.
If you have started to drive, stop immediately and call for roadside assistance. Even if the petrol has started to corrode parts of the diesel fuel pump, it may still be an affordable repair to replace seals and recalibrate the fuel pump.
Regardless of the distance travelled, have your car taken to your vehicle’s authorised service centre or the nominated service centre for your car insurance. They have the tools and expertise to ensure no lasting damage has been done.
Accidentally filling up with the wrong fuel often voids the warranty on your car, making this an expensive mistake to make.
Avoidance is the best policy. If the fuel intake of your car doesn’t already have a “diesel only” warning label, check with the manufacturer to get a sticker fitted. Adopt a simple change of behaviour every time you fill up; check before putting the nozzle into the tank.
With a wealth of experience in the industry, here at Munster Tyres we are dedicated to helping you look after your vehicle to ensure high performance and longevity. We offer an extensive range of services for highly competitive prices including:
- Tyre Fitting
- Winter Tyres
- Performance and Branded Tyres
- Regular Tyres
- Wheel Balancing
- Mobile Fitting Service
- Car Servicing and Repairs
- MOT
- Brake and Clutch Repair and Replacement
To learn more about how your vehicle can benefit from our services, don’t hesitate to get in touch with our expert team today.