So you’ve put the wrong fuel in your car; petrol into a diesel engine or diesel into a petrol engine. What happens now?
Whatever you do, do not start the engine! Hopefully you realise your mistake before the engine is started, but if not don’t worry.
It’s more likely for petrol to be put into a diesel engine because the petrol nozzle can easily fit into the diesel fuel tank.
Petrol in a diesel tank is worse, not only is this an easier mistake to make, it is very damaging to the engine as petrol acts as a solvent and can damage the fuel pump, the injectors and filters- worst case scenario the engine needs replacing.
If diesel is put into a petrol engine, the likelihood is that the vehicle probably will not start. Diesel is heavier than petrol and doesn’t mix very well.
What happens when the wrong fuel type is put into the engine?
Regardless which way round, putting the wrong fuel into a car will require a complete flush of the tank to remove the fuel.
Starting the engine allows the fuel to move around the engine which is when the most damage is caused and can be expensive to rectify.
If the wrong fuel type has been put into a car the best-case scenario is the engine hasn’t been started and the mistake is realised immediately, in which case a complete flush of the fuel tank by a specialist should remove the contaminated fuel. Prices for this service vary but will be in the £100-£300 mark.
Worst case scenario the car has been driven before realising. This could cause serious damage to fuel pump and other engine of components. A repair like this could cost thousands of pounds and will also start with flushing the fuel tank.
Symptoms of wrong fuel
It is possible to put the wrong fuel in a car and not realise. Putting petrol into a diesel car is the most likely situation. You may not realise and continue to drive, however the car will start to lose power, over heat and eventually breakdown.
Putting diesel into a petrol car is an unlikely scenario however if it happens this way it’s unlikely the car will start. As mentioned above diesel is heavier than petrol so they don’t mix and you will realise there is a problem pretty quickly.
What is the repair process/How do you drain the incorrect petrol?
- Draining or emptying incorrect fuel
- Remove mixed fuel from the fuel lines
- Put 5-10 litres of the correct fuel into the tank- this should be pumped through and flush out the remaining
Specialist equipment is needed so it’s a process completed by professionals.
Is wrong fuel covered by insurance?
Depending on coverage, yes. If you have fully comprehensive cover, putting the wrong fuel may be covered under the accidental damage clause. This may only cover flushing the engine and not necessarily rectifying any engine problems that were caused as a result of misfuelling.
With breakdown cover you’ll probably be able to get the fuel pump drained and the vehicle taken to the nearest garage. If there’s any lasting damage, depending on coverage that will be an additional cost.
Misfuelling happens more often than you think. The main thing is not to start the vehicle and contact your breakdown and insurance provider to see what options are available. Additionally, it is possible to get a diesel fuel cap attached to your fuel neck to prevent a petrol nozzle from being able to enter. The price varies due to make and model but is in the region of £15-£20.