What to Do If You Put Petrol in a Diesel Car in Cambridgeshire
Updated: Sep 11
Putting petrol in a diesel car is a mistake that happens more often than you might think. If you find yourself in this situation in Cambridgeshire, it can be stressful and confusing. Knowing the right steps to take can save you from costly repairs and get you back on the road quickly. This guide explains what happens when petrol goes into a diesel engine, how to handle the situation, and where to find help in Cambridgeshire.
Why Putting Petrol in a Diesel Car Is a Problem
Diesel and petrol engines work differently. Diesel engines rely on compression to ignite the fuel, while petrol engines use spark plugs. Diesel fuel lubricates the engine’s fuel system, but petrol acts as a solvent and can damage these parts.
When petrol enters a diesel engine, it can cause:
Damage to fuel injectors and fuel pump because petrol does not lubricate these components.
Engine knocking or misfiring due to improper combustion.
Clogged fuel filters as petrol can cause deposits.
Potential engine failure if the car is driven with the wrong fuel.
The severity depends on how much petrol was added and whether the engine was started.
Immediate Steps to Take If You Put Petrol in Your Diesel Car
If you realize you have put petrol in your diesel car, act quickly to minimize damage.
Do Not Start the Engine
Starting the engine circulates the petrol through the fuel system, increasing the risk of damage. If you have not started the car, do not turn the ignition on.
Stop Refuelling Immediately
If you notice the mistake while still at the pump, stop filling the tank. The less petrol in the tank, the easier it is to fix.
Call for Professional Help
In Cambridgeshire, we specialist in fuel system issues. We can drain the tank and flush the fuel system safely.
What Our Professionals Will Do to Fix the Problem
Drain the fuel tank completely to remove all petrol.
Flush the fuel lines and replace fuel filters to clear any petrol residue.
Inspect the fuel pump and injectors for damage.
Refill the tank with diesel and test the engine.
In some cases, parts like the fuel pump or injectors may need replacement if damaged.
How Much Does It Cost to Fix Petrol in a Diesel Car?
The cost varies depending on the amount of petrol added and whether the engine was started. Typical costs in Cambridgeshire range from:
£150 to £600 for draining and flushing the system.
£600 to £1,000 or more if fuel pump or injectors need replacement.
Getting help early reduces the risk of expensive repairs.
Preventing Petrol in a Diesel Car Mistake
Avoiding this problem is better than fixing it. Here are some tips:
Always check the fuel type before refuelling. Look for the diesel label on the pump.
Use diesel-only petrol stations if possible. Some stations in Cambridgeshire clearly separate fuel types.
Keep a reminder sticker near your fuel cap.
If you rent or borrow a car, double-check the fuel type.
What to Do If You Started the Engine
If you started the engine after putting petrol in your diesel car, the risk of damage increases. In this case:
Turn off the engine as soon as you notice something wrong.
Avoid driving the car.
Call our professional wrong fuel drain service immediately.
Do not attempt to fix the problem yourself.
Driving the car can cause petrol to circulate through the fuel system, leading to costly repairs.
Signs Petrol Is in Your Diesel Car
Sometimes you may not realize the mistake immediately. Watch for these signs:
Engine warning lights on the dashboard.
Rough idling or engine misfires.
Difficulty starting the engine.
Loss of power or unusual noises.
Smoke from the exhaust.
If you notice any of these symptoms after refuelling, stop driving and get your car checked.
