Petrol in diesel · urgent guidance
Petrol in a diesel car: what to do now
If petrol has gone into a diesel vehicle, leave the engine off. If you have already started or driven it, stop safely, switch off and do not restart. Fuel Drain Scotland can assess and drain the vehicle at a suitable location across Scotland.
Call 07961 332486Fuel drains from £119 + fuel · Travel costs may apply
Immediate steps
Do these three things now
- Do not start the carKeep the key away from the ignition where practical and do not press the start button.
- Tell the site staffIf you are at a filling station, let staff know and ask where the vehicle can safely remain.
- Call with the detailsShare the registration, exact location, fuels involved, approximate amount and whether the engine ran.
Why petrol in diesel needs attention
Diesel fuel helps lubricate parts of a diesel fuel system. Adding petrol changes the mixture and can reduce that lubrication. The practical risk depends on the vehicle, the amount added and whether the mixture has circulated.
There is no useful benefit in starting the engine to “see if it is all right”. Keeping the engine off gives the contaminated fuel the best chance of remaining mainly in the tank, where it can be removed before the vehicle is run again.
Can petrol be drained from a diesel at the roadside?
Often, yes. A mobile fuel-drain unit can attend the vehicle, assess what happened, remove the contaminated fuel and flush the system as appropriate. Enough correct fuel can then be added to help get the vehicle moving; that fuel is charged separately.
The location must be safe and accessible. A home driveway, workplace, car park or filling-station forecourt may be suitable with the owner or operator’s permission. If the vehicle is in a dangerous position or the circumstances need workshop equipment, recovery may be the safer next step.
What the technician needs to know
A short, accurate account helps the team prepare the right response. Do not guess if you are unsure—say what you know and what you do not.
- The vehicle registration, make and model
- Your exact postcode, road or live map location
- How much petrol was added and how much diesel was already present
- Whether the ignition was switched on, the engine started or the vehicle driven
- Whether you are somewhere safe and whether site permission is needed
Customer feedback
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Questions about this wrong-fuel situation
Advice reviewed by Fuel Drain Scotland LTD
Last updated 11 September 2026
Can I dilute petrol in diesel by adding more diesel?
Do not rely on dilution without vehicle-specific professional advice. The safer immediate action is to keep the engine off and have the situation assessed.
What if I drove after putting petrol in diesel?
Stop as soon as it is safe, switch off and do not restart. Tell the technician how far the vehicle travelled and any symptoms you noticed so the response can be assessed properly.
Will I always need recovery?
Not always. Many fuel drains can be completed at the vehicle, but unsafe access, a breakdown position or signs of further damage may make recovery or workshop diagnosis more appropriate.