MOTORISTS are being warned to be extra careful when filling up their cars, with incidents of "mis-fuelling" on the rise.
The numbers of drivers putting the wrong fuel into their cars has been increasing steadily in line with the growth in popularity of diesel-powered passenger cars.
RACQ technical and safety policy executive manager Steve Spalding said it was too easy to pick up the wrong pump nozzle, particularly if there were multiple fuel choices at the same bowser.
"Inconsistent labelling has added to the confusion, with retailers using different colours for different fuels," he said.
Matthew Luke, owner of Queensland Diesel and Automotive Diagnostics at Goodna, has experienced first-hand the pain drivers feel when they find out how much the mistake will cost them.
Mr Luke said some people recognised the mistake before leaving the service station, but for those who didn't, the mistake quickly became an expensive one.
"If you start the engine and then you notice you have a problem, unfortunately the damage is already done," Mr Luke said.
"It's not anything to spend $6000-$7000 at least to repair the fuel system on the car.
"I had a customer who recently did it on a late-model Holden, and the bill was just short of $10,000 on a $35,000 car."
Drivers who recognise the error before turning the key can have the tank drained and the fuel system purged.
Despite differing fuel types being delivered through different sized nozzles, Mr Luke said diesel drivers were at the highest risk.
"You couldn't fit a diesel nozzle into an unleaded hole, but it's very easy to fit that small unleaded nozzle into a diesel vehicle."
The rise in incidents has led to the development of new technology to address the problem.
Limited new diesel cars in Europe, where diesel passenger car sales are equivalent to petrol, are now fitted with a device to detect petrol vapour in the fuel neck and then trigger a lock-off valve.