Can you dilute petrol with diesel?

No. Topping up doesn't take the petrol out. It just spreads it through more fuel.

You'll read online that a litre or two in a full tank is fine. That isn't advice we'd tell you to follow. Nowadays, with high pressure fuel pumps, common rail setups and high pressure injectors, the tolerance is very, very low. Running it can mean a costly repair. It depends on the vehicle.

Your pump runs on whatever comes out of the tank. Diesel is what keeps it lubricated. A bigger tank of mixed fuel is still mixed fuel. Leave it off and ring us on (08) 7083 9699. We drain, clean the tank and you fill up with clean diesel.

What about a bit of diesel in a petrol car?

Same answer, different reason. A petrol engine lights its fuel with a spark. Diesel doesn't burn properly in a petrol engine.

You may get smoke, misfires or rough running. Diesel can clog the spark plugs and fuel system. Running it can also damage the catalytic converter.

Topping up with petrol doesn't change any of that. Leave the ignition off. The wrong fuel needs draining before the car is run. There's more on our diesel in a petrol car page.

Here's a real one: diesel in a Porsche Cayenne at Hyde Park.

Will a fuel additive fix it?

No. Nothing you pour in takes the wrong fuel back out.

You'll hear about adding two stroke oil to put the lubrication back. It doesn't take the wrong fuel out. The only fix is to drain it.

Still at the pump?

Leave it off. Our first 60 seconds post walks you through the next few minutes. Or just ring us on (08) 7083 9699, day or night.