Petrol in a Diesel Car: Mobile Fuel Drain
If you have put petrol in a diesel car, leave the engine off and the key out of the ignition. While the engine has not run, the petrol is still in the tank, and a drain is usually all the car needs. We come to the car and do it where it is, on the forecourt, at the roadside or outside your home.
What petrol does in a diesel engine
Diesel does two jobs on its way through the engine. Before it burns, it lubricates the high-pressure pump and the injectors as it passes through them. Petrol thins the diesel and strips that lubrication away, so the parts that need it most get less of it.
A diesel with petrol in the tank will usually still start and drive for a few miles, which is why people often get away from the pump before they notice anything is wrong. Driving any distance on the mixture is what can do harm, so the sooner the car is stopped, the simpler the job.
Petrol in diesel: what to do now
- Leave the engine off, and don't switch the ignition on, because on many diesels that alone starts the fuel pump priming.
- Don't top up with diesel to dilute it. Topping up removes none of the petrol.
- If the car is blocking a pump, put it in neutral and push it clear. The forecourt staff will usually help.
- If you have already driven, pull over somewhere safe and switch off.
- Call 0333 366 0103 and tell us where you are, roughly how much went in and whether the engine has run.
What we do when we get to you
We check what went in and whether the engine has run, then drain the tank. We flush the fuel lines and the filter so none of the petrol is left in the system, refill with clean diesel, prime it and start the engine to check it runs properly. The whole job is done where the car is, so it never needs to go to a garage, and when it is caught early, lasting damage is very rare.
What it costs
There is no fixed price on this page, because jobs differ. What changes it most is whether the engine has been started or driven, and after that how much went in against the size of the tank and where the car is. Ring with those details and we can tell you what the job will involve.
Petrol in a diesel near you
Each town we have a page for has its own petrol in a diesel page, with the forecourts and roads around it. The counties are listed at the foot of this page, and each one leads to its towns. If yours is not listed, ring anyway.
If you want the tank size for your car, the vehicles section has a page for every diesel model we hold figures for.
Questions about petrol in a diesel
Is a small amount of petrol all right if I just drive it?
We wouldn't. A small amount in a big tank is exactly when people are tempted to chance it, and it is running the engine on the mixture that does the damage. With the car switched off, a drain clears all of it.
Does super unleaded count as petrol here?
Yes. Any grade of petrol in a diesel tank needs draining.
Will my car be all right?
It is very likely to be. Lasting damage is rare when the car is stopped soon and the tank is drained and the system cleaned, and that is what we do where you are.
Are you open at night and at weekends?
We are open 24 hours, so ring whenever it happens.