Misfuelling - What to Do If It Happens to You

LONDON--March 5, 2013:

The AA estimates that as many as 150,000 of us put the wrong type of fuel in our vehicles every year.

The AA website suggests that the rise in incidents of 'misfuelling' may be attributable to the rise in sales of diesel-fuelled cars. Traditionally thought of as running particularly noisy engines, diesel engines have been getting increasingly quieter and - particularly in the case of rental cars or second cars - it's easy to forget you're driving a car with a diesel engine.

The high-pressure fuel pump in a diesel engine is very sensitive, and adding petrol serves to strip it of essential lubrication. As metal grinds against metal without diesel's lubrication, the fuel contaminated with loose metallic particles soon affects the rest of the fuel system. And the further the contaminated fuel travels, the worse the problem gets. Common rail (or HDi) diesel engines are particularly sensitive, and extensive contamination could necessitate the replacement of multiple, costly components.

Putting diesel in a petrol engine has also been known to end badly. Spark plugs will be contaminated by the oily fuel, the engine will suffer detonation and produce smoke from the exhaust. Luckily though, this is a less frequent mistake because a standard diesel nozzle is incompatible with the filler neck on today's petrol-driven vehicles.

In both cases, the AA advises that you don't turn on the ignition or start your vehicle if you've added the wrong fuel. They also advise that contaminated diesel should be removed from the tank and replaced with clean fuel as soon as possible - again it's crucial this is done before you start your vehicle or turn on the ignition.

Some policies don't cover misfuelling, so it's worth checking when choosing car insurance. But whether you have AA insurance or not, AA Fuel Assist is now on call to save time, money and inconvenience by flushing and replenishing your fuel systems when the need arises. The AA say that Fuel Assist Vans will attend any vehicle in need of help, which means that those in trouble don't even need to be AA members to get back on the road.