Petrol in a Diesel Car What to Do
Putting petrol in a diesel car is one of the most common and serious misfuelling mistakes.
What you do next can be the difference between a quick fix and major engine damage.
This guide explains exactly what to do if you’ve put petrol in a diesel car, what damage can occur, and when to call for professional help.
First things first – Do NOT start the car
What to do immediately if you put petrol in a diesel car
If you realise you’ve put petrol in a diesel vehicle:
Do NOT start the engine
Do NOT turn the ignition on
Do NOT attempt to drive
Call a professional wrong fuel recovery service immediately
If the engine has not been started, serious damage can often be avoided.
Why petrol in a diesel car causes damage
Diesel fuel provides lubrication for critical engine components.
Petrol does not.
When petrol enters a diesel fuel system it can:
- Strip lubrication from fuel pumps
- Damage high-pressure injectors
- Cause metal-to-metal contact
- Lead to catastrophic fuel system failure
Modern diesel engines are especially sensitive due to high-pressure systems.
What happens if you drive a diesel car with petrol in it?
Starting the engine allows petrol to circulate through the system.
This can result in:
- Injector failure
- Fuel pump damage
- Engine stalling
- Contaminated fuel lines
- Very expensive repair bills
In some cases, continued driving can require full fuel system replacement.
Is a small amount of petrol in a diesel car dangerous?
Even a small amount of petrol can cause issues if the engine is started.
Risk depends on:
- How much petrol was added
- Whether the engine was started
- How long the vehicle ran
Because the risk is unpredictable, professional assessment is always recommended.
Can the car be repaired?
Yes — in many cases.
If dealt with early:
- The fuel tank can be drained
- The system flushed
- The correct diesel fuel added
- The vehicle returned to normal operation
The earlier the response, the better the outcome and the lower the cost.
Common mistakes to avoid
Do NOT:
- Try to “dilute” the petrol with diesel
- Drive the car to “burn it off”
- Start the engine “just to check”
- Attempt DIY draining
- Attempt to find out how long a car will run with the wrong fuel
These actions often turn a simple fix into a major repair.
When to call a wrong fuel specialist?
You should seek professional help if:
- Petrol has been added to a diesel car
- You’re unsure if the engine was started
- The vehicle won’t start
- Warning lights appear
A specialist can advise you immediately and attend your location if required.
Put the wrong fuel in your car? Don’t start it.
24/7 Emergency Wrong Fuel Recovery
See the Areas We Cover
View more frequently asked questions