Monday, March 7, 2016


It’s not every day that you put the wrong type of fuel in your car, but it does happen. If you find yourself in this unfortunate position you’ll probably be wondering what’s going to happen...

Diesel needs pressure to be ignited, it is also heavier than petrol and much more “oily”. If you try to start a car with diesel in a petrol engine the spark plugs won't be able to ignite the diesel and the engine won't start.

To fix this problem you will need to drain the tank and fill it again with petrol as well as clean the injectors. As an extra precaution you may want to change the fuel filter.

Putting petrol in a diesel engine is a bit more complicated. Modern diesel engines operate at high pressure and with fine tolerances. The “oiliness” of the diesel is to act as a lubricant for the engine. When petrol is added it acts as a thinner and causes the engine and fuel pump to wear down through friction. If things have progressed this far you will need to flush the system and replace any damaged components.

Trying to start the engine can cause additional damage. Petrol is more volatile than diesel and when subjected to high pressures the petrol can combust prematurely, forcing the pistons to to rise and fall out of their order. This can have disastrous effects on the internal components of an engine block.

The bottom line is that if you find that you’ve mistakenly put the wrong fuel in your car DO NOT turn on the ignition. You should drain the tank before the fuel has been circulated to avoid damage.

If you need a tow and the assistance of our service team - give us a shout!


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