AA Fuel Assist

Apart from making funny noises, what happens if you happen to put the wrong fuel in your car?

Can you just act like nothing has happened to put the right fuel in, or will it cause significant damage to your car?

Misfuelling can cause several issues due to the following:

• Diesel fuel pumps operate on very fine tolerances and are lubricated by the diesel fuel itself.
• Petrol in diesel acts as a solvent – it reduces lubrication and can cause damage to the pump through metal to metal contact.
• The further the contaminated petrol goes in the system the more expensive the repair – it can be cheaper in more extreme cases to fit a new engine.
• The newer common rail (or HDi) diesel engines are particularly vulnerable – if fuel contaminated by pump wear debris gets as far as the common rail system you may have to replace the low and high-pressure fuel pumps, injectors, fuel rail, line filters and the fuel tank too.
• Many systems use a low-pressure electric pump in the tank or sender unit and this begins to work as soon as the ignition is switched on, circulating the contaminated fuel through the pump and rail – so it’s important not to turn the ignition on.
• Damage to the engine can be very expensive for some vehicle owners: manufacturers often:
  • Recommend change of parts (as high as €2,000* or more) and
  • Garages often charge €440* or more for a fuel drain

You weren’t paying attention and lifted the green bump instead of the black. When your car starts acting up, or you realise what you’ve done, DO NOT turn on the ignition or start the car.

If the car’s still under warranty, you should check with the franchised dealer regarding their advice and correct remedial action – running with even a small amount of petrol in the tank might invalidate the warranty, while some manufacturers advise that seals and filters should be renewed even if the engine has not been run.

A quick slip and you’re pumping diesel in the car without realising. When this happens, there are a few things to expect.

Making sure that you don’t turn on the ignition or start the car, it helps to know that you have to be pretty determined and patient to misfuel with diesel. Diesel in petrol is less common because the standard diesel nozzle at fuel stations is larger than the fuel filler neck on modern petrol cars

Again, if the car is still under warranty, you should check with the franchised dealer regarding their advice and correct remedial action.

Call +353 1 649 7460 now.

You’ll get connected to one of our nationwide roadside assistance experts, who can help you see what options you have.

And for those AA members who have had a problem in a car they’re a passenger, remember that your membership covers YOU, so we can come and help.