Diesel in a petrol? We'll sort it.
Less common, because a diesel nozzle is usually wider than a petrol filler, but it happens, especially with older cars and some pumps. It still needs draining.
What we actually do.
Switch "Engine started?" to Yes to see why stopping straight away matters.
How we fix itPick what happened, then press and hold the button.
1 · Drain the wrong fuel
Ignition off
Keep it off until the fuel's drained.
A simplified view of a real job. Every vehicle is different, so call us about yours.
Then we clean the lines.
If the engine ran, the wrong fuel isn't just in the tank. It's in the fuel lines, the filter and the injector rail too.
Cleaning the fuel linesIf the engine ran, the wrong fuel is in the lines, the filter and the injector rail, not just the tank. Hold the button to flush it through.
Contaminated fuel in the lines
Clean fuel is pushed through from the tank end and the contaminated fuel comes out into a sealed jar.
What happens
Petrol engines aren't designed to burn diesel. It's heavier and oilier, so it doesn't ignite properly in a petrol engine. It can coat the spark plugs and fuel system, which leads to misfiring, smoke and the engine cutting out. Left in the tank with the ignition off, it's a simple drain.
Signs if it's been driven
If you didn't notice at the pump, these are the usual signs. Pull over safely, switch off and call us.
- Misfiring or spluttering
- Lots of smoke from the exhaust
- Engine cutting out
- Won't start, or struggles to start
- Engine warning light on
- Rough idle
How we fix it
We drain the diesel and petrol mix, flush the lines and refill with clean petrol.
- 1
Drain
We pump the wrong fuel out through the filler neck, fuel lines or sender unit.
- 2
Flush
We flush the fuel lines so contaminated fuel isn't left in the system.
- 3
Refill
The right fuel goes in. Fill to at least three-quarters to dilute anything left.
- 4
Drive
Receipt sent to your phone. Book a new fuel filter at a garage soon.
Afterwards
- Fill to at least three-quarters with the right fuel to dilute any small trace left.
- Have the fuel filter replaced at a garage as soon as you can.
- If a warning light stays on, or it runs roughly, stop and get it checked, and let us know.
- Keep your receipt for any insurance claim.
If the engine ran on the mix for a while, your garage may also want to check the spark plugs.
Questions
Is diesel in petrol as bad as petrol in diesel?
It's usually less likely to cause expensive damage, but it still stops most petrol engines running properly. Don't start it; get it drained.
How did diesel even fit?
Diesel nozzles are usually wider, but some fillers and some nozzles are close enough in size, and older vehicles may not have the narrower filler. It's more common than you'd think.
Can I drive it to a garage?
We wouldn't. Driving on a mix risks misfires and cutting out on the road. We come to you instead.
We fix all of these.
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The four things to do in the next five minutes.
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