One In Ten Motorists Mis Fuel At The Pumps


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According to a recent survey conducted by AA Ireland*, 10% of Irish Motorists have accidently put the wrong fuel in their engine. The AA Fuel Assist team reports attending to up to 200 incidents to date in 2010, the majority a result of petrol into a diesel engine.

‘There has been a growing trend in motorists shifting to diesel fuelled cars since the government’s rise in carbon taxes and VRT changes as motorists switch to more energy efficient cars’ says Conor Faughnan, Director of Policy. According to recent CSO figures on new car sales, 34.2% were petrol and 62.1% were diesel.  However, one of the consequences of switching engines is a mis-fuel at the pumps. Old habits die hard. Many motorists admitted to filling up with petrol in error after changing engines when concentration levels were low.

The research showed motorists were most likely to inject the wrong fuel while using a rented or borrowed car. Motorists have reported a number of distractions at the pumps for personal reasons, haste, advertisements, poor lighting, distracted attendants and unclear markings of fuel. There are cases where motorists mistake bio-diesel for diesel. Nozzle restrictors are not always in force at all stations. Motorists must remain alert as colours and procedures are not consistent across all stations, another reported cause of error.

Overall results convey men were 5% more likely to misfuel than females. Only 5% of motorists under the age of 25 have accidentally misfuelled. This is in contrast to 15% of over 65 year olds.

‘Damage to the car can be very expensive for some vehicle owners’ says David Murphy, AA Technical Services.   ‘In some cases where the contaminated fuel has been drawn into the fuel system the repair could run into thousands of euro. Even when the car has not been started, garages face a long and labour intensive job to drain and clear the system, and they will charge accordingly. AA Fuel Assist replenishes and recycles the fuel for €260’. (prices start at €236 for AA members)

The AA wishes to offer the following advice to motorists in the event of a misfuel;
·         Do not turn on the ignition or start the engine as this will circulate the contaminated fuel and increase the risk of damage.
Generally a small amount of incorrect fuel should not damage the engine as long as you have not started the car and top up fully with original fuel.
If the car’s still under warranty you should check with the franchised dealer regarding their advice and correct remedial action.
Petrol In Diesel

If the car’s still under warranty you should check with the franchised dealer regarding their advice– 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.

·         If you’ve added more than 10% (5 litres in a 50 litre tank) petrol – Drain the tank and refill with diesel
·         If you’ve added less than 10% petrol  – Top up with diesel and run normally unless the manufacturer has advised otherwise
Diesel In Petrol

This is much less common because the standard diesel nozzle at fuel stations is larger than the fuel filler neck on modern petrol cars – you have to be pretty determined and patient to misfuel with diesel as a result.

·         If you’ve added more than 10% (5 litres in a 50 litre tank) diesel – the car shouldn’t be run and the tank should be drained
·         If you’ve added less than 10% diesel – the tank can be topped up with petrol and the car run normally unless the manufacturer has advised otherwise
CALL 1890 456 226 or log onto for further info on Fuel Assist services.
*AA online survey carried out as part of AA Motorists’ Panel research, 7,000+ responses received between 23rd April to 12th May 2010.