Diesel in a Petrol Tank

The country’s leading Diesel in Petrol specialists

Diesel in a Petrol Car

Accidentally Put Diesel in a Petrol Car By Mistake and Drove It?

Putting the wrong fuel in your car is more common than many people think. Every year in the UK, thousands of drivers accidentally put diesel in a petrol tank. It’s a simple mistake, but one that can have serious consequences for your vehicle if not addressed quickly.

FuelFixer, a leading fuel draining service operating nationwide, is here to help you understand what happens when this mistake is made—and what you should do about it.

Modern diesel vehicles are highly sensitive to the quality of fuel and filling diesel car with petrol can ruin the engines quite quickly. Fortunately, you can limit potential damage if you realize your mistake sooner.

Why Does Misfuelling Happen?

With modern petrol and diesel fuel caps looking more similar than ever, and many drivers switching between petrol and diesel vehicles, it’s surprisingly easy to put diesel in a petrol tank. Whether you’re in a hurry, distracted, or using a hire car, one wrong move at the pump can lead to a stressful situation.

Diesel nozzles are usually larger than petrol ones, which makes it harder to fit a petrol nozzle into a diesel car. But unfortunately, the reverse—fitting a diesel nozzle into a petrol tank—is relatively easy.

You’ll then have to call a fuel removal service to drain your car’s fuel tank, flush the engines, and help you get back on the road as quickly as possible.

What Happens When You Put Diesel in a Petrol Tank?

Petrol engines are not designed to handle diesel fuel. Petrol is more volatile than diesel, and it’s meant to ignite from a spark created by spark plugs. Diesel, on the other hand, is heavier and ignites through compression. When diesel is introduced into a petrol engine, several problems can occur:

Costly Repairs: If the engine is started and diesel circulates through the system, repair costs can skyrocket due to internal contamination.

Poor Combustion: Diesel doesn’t evaporate like petrol, so it won’t burn properly in a petrol engine. This leads to poor ignition and performance issues.

Engine Misfiring: You may notice that the engine struggles to start or runs unevenly.

Clogging of Fuel System: Diesel is oilier and can clog petrol fuel injectors and spark plugs, causing potential damage to components like the catalytic converter.

Prevention Tips

While mistakes happen, here are a few tips to help avoid putting diesel in a petrol tank in the future:

Label your fuel cap: A small sticker noting “PETROL ONLY” can be a helpful reminder.
Stay focused at the pump: Avoid distractions and double-check the nozzle before filling up.
Use a misfuel prevention device: These are relatively inexpensive gadgets that prevent the wrong nozzle from fitting into your fuel tank.
Know your hire car: Always check what type of fuel the vehicle takes before filling up.

Immediate Steps to Take

If you realise you’ve put diesel in a petrol tank, the most important thing to remember is not to start the engine. Starting the car will circulate the diesel through the fuel system, making the problem much worse and more expensive to fix.

Here’s what to do instead:

Stop immediately: If you’re still at the pump, don’t turn the key.
Alert the station staff: They may help you move the vehicle safely out of the way.
Call FuelFixer: Our mobile fuel drain experts operate all across the UK, and we can come to you, wherever you are, usually within an hour.

What FuelFixer Does

FuelFixer specialises in misfuel recovery and has helped over 100,000 motorists across the UK. If you’ve put diesel in a petrol tank, our trained technicians will:

Safely drain the contaminated fuel from your vehicle.
Flush the fuel lines and engine components to remove any residue.
Refill your tank with the correct fuel.
Ensure your vehicle is road-ready before you leave.

We offer a quick, cost-effective alternative to dealership repairs or towing services. Our mobile service vans are fully equipped and can reach you whether you’re stuck at a service station, on the roadside, or at home.

Why Speed Matters

The longer diesel sits in a petrol tank, the greater the chance of damage. Once the engine is started, diesel can cause more harm to sensitive components like fuel injectors, spark plugs, and catalytic converters. These parts are not only expensive but can also take time to replace. Calling FuelFixer immediately helps limit the risk and cost of damage.

Why Choose FuelFixer?

With fast response times, nationwide coverage, and competitive pricing, FuelFixer is one of the UK’s most trusted misfuel recovery services. Our experienced team understands the stress of putting diesel in a petrol tank, and we’re committed to getting you back on the road quickly and safely.

Whether you’re in London, Manchester, Glasgow, or a remote corner of the countryside, we’re just a phone call away. Our 24/7 service means help is always available, day or night.

Final Thoughts

Putting diesel in a petrol tank can be a frustrating and costly mistake, but with the right response, it doesn’t have to be a disaster. Acting fast and calling in professional help can save you time, money, and stress. If you ever find yourself in this situation, remember: don’t start the engine—just call FuelFixer.

Let our experts handle the mess so you can get back to what matters—driving safely.

For more information see our “Petrol in Diesel” FAQs here

Small Amount of Petrol in Diesel Car

Owning a diesel car, putting petrol in it, and driving it may not seem like a big deal at first. Many times, you’re at the diesel pump, and you go to put fuel in your car only to realise it was petrol and not diesel. If you do get small amounts of petrol in your diesel engine, you can lower the flashpoint of the diesel by about 18 degrees Celsius. That means the diesel fuel system is going to prematurely ignite inside the engine, causing damage. Contamination from the petrol can damage your diesel injectors and the fuel pump, as well.
If you do that, you could do significant damage. Misfuelling happens, and it is possible to fix the problem. However, you need to get service soon before you have a breakdown. Remember, you want to stay safe, so you should get advice and call us today!

Put Petrol in Diesel Car: How Much to Fix

If you realise your misfuelling mistake early on, no permanent damage is likely to occur to the fuel pumps and fuel lines. Even though you caught the problem and continued putting diesel in at the petrol station, you could have a breakdown.

What to Do If You Put Petrol in the Diesel Engine

If you’re at the pump and realise you didn’t use diesel fuel in your car, you need to put away the key. Don’t start your engine at all. Even if you don’t start the engine, a newer car automatically notices the key in the ignition, and it signals to the car to prime up the engine to start driving. Adding petrol to your car can cause significant damage to the fuel pump, even though you’re just sitting there.
New cars with keyless entry and push-button start could take you opening the door as a signal to prime up the engine. If you’ve caught yourself adding petrol while at the diesel pump, call roadside assistance immediately. The representative can dispatch someone to your location. Then, you can get it towed to a service station like us.

I Put Some Petrol in a Diesel Car by Mistake and Drove It

If you’ve already started driving, you may not realise your mistake until it’s too late. Misfuelling can take time to work through. Therefore, if you turned on the ignition and drove to London, you may notice something wrong. Though it doesn’t always cause a breakdown, it can. In this case, you should get the car to a safe place, which is what the breakdown lane is for. Turn off the ignition immediately and put on your hazard lights. Call a tow truck, roadside assistance, or a mechanic. You may also contact your car insurance representative to let them know what’s going on. He or she can help you find the right service company to help.
Once you find someone to help, there is a process to fix the problem. First, someone has to drain the fuel tank. We don’t recommend that you drain it yourself. Instead, contact a professional. Depending on where you noticed the problem, the fuel pumps, injectors, and fuel rail may have extensive damage and need to be replaced.
In a sense, the more fuel that gets into the engine, the more expensive it is going to be to get it fixed.
Some believe that a little petrol in the diesel tank can be fixed and that engines can tolerate about 10 percent contamination. This is true for older diesels, but the newer ones are more environmentally-friendly and efficient. Therefore, they’re less tolerant about mixing fuels.
If you can catch it early enough, such as when you’re at the pumps, here is our advice: Drain out the petrol fuel and refill it with the correct fuel. You aren’t likely to have problems.

Petrol in Diesel Car Symptoms

The best tips we can provide are to pay close attention when filling up at the pumps and to know what’s going to happen if you put petrol in a diesel engine. To start, let’s look at the symptoms of putting in the wrong fuel, some of which might be noticed soon after the accident:
– Loud knocking noise while you accelerate
– Loud knocking noise while you accelerate
– Excessive smoke from the exhaust system
– Rough idling
– Hard to accelerate
– Engine warning light appears
– Car stops completely
– Misfiring engine
– Car doesn’t want to start again after being shut off

20 Litres of Petrol in Diesel Car

In our ‘Petrol in Diesel Car Forum,’ you may see that people have talked about adding specific amounts of petrol to their diesel vehicle. There is no ‘magic’ safe number that can go into the system without doing damage. Our best advice is that you need to remove the wrong fuel and add new diesel to the car. However, it’s even better to avoid a breakdown and request service from a reputable company. We can help you get the wrong fuel out and assess the damages.
The amount of litres of petrol added has to be much less than the tank capacity. Most new vehicles can carry between 45 and 65 litres of fuel. Sometimes, cars have secondary fuel tanks, which contain about 15 percent of the primary chamber. Let’s say you have a 60-litre fuel tank. What’s going to occur if you add 20 litres of the wrong fuel? You’ve still got 40 litres to go, which is much more than the 10 percent contamination number that most people go by. Therefore, you should be able to safely add diesel until the pump shuts off without damaging anything. These tips might not always work, depending on the age of the car and other factors.

How Far Can You Drive with Petrol in a Diesel Car?

Our advice is that you need to stop driving when you notice that you added the wrong fuel to the vehicle. This is going to make it safer and could reduce the damages. You may find that you drive away after you accidentally put the wrong fuel in the tank and nothing goes wrong. Just make sure that you are careful.
The best advice we can offer is that you need to know if you own a modern diesel and what injection system you have. That way, you know which fuel you need in the tank. The filling station probably uses different sized nozzles for each type of fuel. That way, you have a lower chance of grabbing the wrong one. If you put the wrong fuel in your car, we’re here to help. Those with a petrol engine have less to fear. It’s not as bad to put diesel in a petrol car.
It’s important to know what happens when you add petrol to a diesel vehicle. Get the latest news, tips, and advice on our website. Though knowing what happens when you put diesel in a petrol engine is also essential, it might not be as bad. A petrol car and petrol engine don’t usually do as much harm. Adding diesel in a petrol car is still not good, but it isn’t going to be as bad if you start the engine or put the key in the ignition.
Make an appointment today!

What Are the Symptoms of Putting the Petrol in a Diesel Vehicle?

All fuels are made with crude oil, and many people feel that they can switch out diesel or petrol at the gas station. This is a common mistake to make, but it’s important to know the symptoms you might experience. With that, car buyers should be aware of this, as some people put in the wrong petrol and then try to sell it.
Though very fine tolerances might not be a costly mistake, it’s best to avoid putting the wrong product in the engine at the filling station. The symptoms you experience depend on how much diesel you put into the car. Modern diesel engines use an injection system similar to petrol engines. Putting diesel in a petrol engine could include these issues:

– Smoke coming from the engine or exhaust
– The car simply doesn’t go or start
– Misfiring engine

It’s an easy mistake to make, but the good news is it might not do serious damage.
To avoid unnecessary damage, it’s best to take your vehicle to a car care location like Fuel Fixers. When the tank is full of the wrong product, it increases friction on the metal parts and can lead to severe problems. Your ignition might not work at all, or it might smoke a lot.

What Can You Do If You Put Petrol in Your Diesel or Diesel in Your Petrol Car By Mistake?

The best thing to do is not start the engine. Some experts even say that you shouldn’t use your remote to unlock/lock the car. Though we concur, we know that you might not realise you put the wrong fuel in your car until you’re miles away from the petrol station and have a stall.
However, you can rest easy knowing that your car should be fine after a fuel drain of the fuel tank.
Overall, a petrol engine has spark plugs, which a diesel car doesn’t. Regardless, the biggest mistake people make is to think their breakdown cover is what they need. However, you still need to take it to a professional to have the tank drained and cleaned, and that’s where we come in.
If you do notice it while you’re at the station, tell the staff what happened. Don’t get embarrassed because it occurs frequently, and they should be understanding. Call us and let us know what happened, and we can send an engineer to your location.

Why Should You Use Fuel Fixer Instead of Another Company?

Most people don’t even realise that there’s a need for the wrong fuel removal industry until they’re in a situation with their car’s engine. You’re upset and stressed, which makes it hard to think clearly. There are companies out there that might not have the tools to do a drain and might even subcontract the work.
Diesel vehicles require a specialist to work on them, and we have the skills and equipment necessary to handle the job.

If You Put the Wrong Fuel In Your Vehicle, Should You Call Your Roadside Assistance Provider?

You can call your car insurance company to use its breakdown service, but this is often expensive. Unless you have wrong fuel breakdown cover (and most car insurance companies don’t offer this), it’s often best to call Fuel Fixer.
Often, the insurance only tows you home or to your main dealer or a local garage. This means more time and hassle from you. When you call us, we come to you quickly with the right tools to get the diesel fuel out of your car.

What License Does a Fuel Fixer Engineer Require?

A professional here should have an ADR license and SPA passport. It’s unsafe to work at the station or transport contaminated fuel without them.

If Your Vehicle Fuel System Requires Repair, Is It Expensive?

It primarily depends on your car. Most of the time, fuel systems aren’t damaged unless you’ve been driving the gasoline car for a long time with a bad fuel mixture. For example, this happens when you put a bit of unleaded fresh gasoline into your diesel engine and top it up with more diesel. Sometimes, damage occurs to the fuel pump because there isn’t enough lubrication from the unleaded petrol in the fuel line.
Most people worry that they must replace their fuel pumps, but often, a drain and flush with a new fuel filter is all you need.

How Can You Prevent Putting Petrol in a Diesel Car?

In most cases, a drain is necessary on a diesel engine with unleaded petrol in your fuel tank. This is because the diesel nozzle doesn’t fit into an unleaded tank. Overall, diesel nozzles are much bigger than petrol nozzles. If you’re worried about adding the correct fuel to the tank, you may use misfuelling prevention devices.
Other tips include:

– Look at the note inside the filler neck flap that tells you to use the right fuel.
– Put a sticker on the cap to remind the driver of the appropriate type.
– Check to make sure that you’re not at diesel pumps when filling up.
– Purchase a device to prevent misfuelling. Check to ensure that it fits your vehicle’s make and model.

What Does Petrol Do to the Diesel Car’s Fuel System?

Putting petrol in a diesel car rarely does anything that you can see for yourself, other than smoke in the exhaust. However, when you open up the diesel tank, you see that the petrol turns black. Overall, the petrol dissolves the rubber.

Is It Worse to Have Petrol in a Diesel or Diesel in a Petrol Car Engine?

Typically, petrol in diesel engines makes it stall or have reduced power. Diesel in petrol cars could make it run flat and lose power.
It all depends on how much goes into the petrol engine. Usually, the things that fail first are the fuel injectors and fuel lines.