What to Do If You Put Petrol in Diesel Car: Essential Steps to Follow
- Wrong Fuel Team
- Jun 16
- 3 min read
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Putting petrol in diesel car is a common mistake that can cause serious damage to your vehicle if not handled correctly. If you realize you’ve made this error, acting quickly and following the right steps can save you from costly repairs and long downtime. This guide explains what happens when petrol enters a diesel engine, the immediate actions you should take, and when to seek professional help.
What Happens When Petrol In Diesel Car
Diesel engines rely on the lubricating properties of diesel fuel to keep their fuel system components working smoothly. Petrol, on the other hand, is more volatile and lacks these lubricating qualities. When petrol enters a diesel engine, it can cause:
Damage to fuel injectors and fuel pump due to lack of lubrication
Engine knocking or misfiring because petrol ignites differently than diesel
Clogging and corrosion inside the fuel system
Potential engine failure if the petrol is not removed quickly
The severity of damage depends on how much petrol was added and whether the engine was started after the mistake.
Immediate Steps to Take If You Put Petrol in Diesel Car
Do Not Start the Engine
If you realize you’ve put petrol in your diesel car before starting it, do not turn on the ignition. Starting the engine will circulate the petrol through the fuel system, increasing the risk of damage.
Stop Refueling Immediately
If you notice the mistake while still filling up, stop refueling right away. The less petrol in the tank, the easier it will be to fix the problem.
Call for Professional Help
Since this situation requires careful handling, contact a specialist who can drain and flush the fuel system safely. Avoid driving the car or trying to fix the issue yourself if you are not experienced.
Why You Should Avoid Driving the Car
Driving a diesel car with petrol in the tank can cause the petrol to circulate through the fuel system, damaging the fuel pump and injectors. This damage can lead to:
Expensive repairs
Breakdown on the road
Safety risks due to engine failure
If you are stranded, call a local breakdown service or a specialist team that deals with wrong fuel incidents.
How Professionals Handle Petrol in Diesel Cars
Specialist teams use equipment to safely drain the contaminated fuel and flush the system. They may:
Remove the fuel tank or use suction tools to extract the petrol-diesel mix
Flush the fuel lines and clean the fuel pump and injectors
Check for any damage caused by the petrol contamination
This process requires expertise and proper tools, which is why local garages or specialist services are the best option.
What to Expect After the Fuel System Is Cleaned
Once the petrol is removed and the system is flushed:
The car should be tested to ensure no damage remains
Fuel filters may need replacement by a local garage
The engine should run smoothly without knocking or misfiring
If you notice any unusual sounds or performance issues after the fix, return to the garage immediately.
Preventing Petrol in Diesel Car Mistakes
To avoid this costly error, consider these tips:
Always double-check the fuel pump before filling up
Use fuel caps or keychains that remind you of your car’s fuel type
Avoid distractions at the pump
If you drive multiple vehicles, keep a mental note or label the fuel types clearly
Summary
Putting petrol in a diesel car can cause serious engine damage if not handled quickly. The key steps are to avoid starting the engine, stop refueling immediately, and call a professional to drain and flush the fuel system. Do not drive the car on motorways or dual carriageways until the problem is fixed, and leave fuel filter replacement to a local garage. Acting fast and following these steps can save you from expensive repairs and keep your car running safely.
